chem wk1 Flashcards
1
Q
what is an anion
A
An anion is a negatively charged ion. It forms when an atom or group of atoms gains electrons. For example, a chlorine atom becomes a chloride ion (Cl⁻) by gaining one electron.
2
Q
what is an atom
A
An atom is the smallest unit of matter that makes up everything around us. It has a nucleus with protons and neutrons in the center, and electrons orbiting around it.
3
Q
where can the atomic number be found
A
the atomic number is the number located above an elements symbol in the periodic table
4
Q
what is the atomic number
A
The atomic number is the number of protons in the nucleus of an atom. It determines which element the atom is. For example, hydrogen has an atomic number of 1 because it has 1 proton.
5
Q
what is a cation
A
A cation is a positively charged ion. It forms when an atom loses electrons. For example, a sodium atom (Na) becomes a sodium ion (Na⁺) by losing one electron.
6
Q
what is the mass number and where can it be found
A
The mass number is the total number of protons and neutrons in an atom’s nucleus. It can be found by adding the number of protons and neutrons together.
You can usually find the mass number listed near the element’s symbol on the periodic table or in the element’s information. For example, carbon has a mass number of 12 (6 protons + 6 neutrons).
7
Q
what is an ion
A
An ion is an atom or molecule that has a charge because it either gained or lost electrons.
8
Q
what is an electron and where can you find it
A
An electron is a tiny, negatively charged particle that orbits around the nucleus of an atom. It is much smaller than protons or neutrons. Electrons are found in regions around the nucleus called electron shells or orbitals.
9
Q
what is a compound
A
A compound in chemistry is a substance made up of two or more different elements that are chemically bonded together. The elements in a compound are combined in fixed proportions.
For example:
Water (H₂O) is a compound made of two hydrogen atoms and one oxygen atom.
Sodium chloride (NaCl) is a compound made of one sodium atom and one chlorine atom.
The atoms in a compound are bonded by covalent or ionic bonds.
10
Q
what is an isotope
A
An isotope is a version of an atom that has the same number of protons (so it’s the same element) but a different number of neutrons. which give them a different mass number
For example:
Regular carbon has 6 protons and 6 neutrons.
An isotope of carbon might have 6 protons and 7 neutrons.
Isotopes are like “siblings” of the same element—they behave similarly but have slightly different masses because of the extra or fewer neutrons.
11
Q
what is the shell
A
In chemistry, a shell refers to the layers or energy levels that surround the nucleus of an atom. These shells contain electrons, and each shell can hold a certain number of electrons.
The first shell can hold 2 electrons.
The second shell can hold 8 electrons.
The third shell can hold 18 electrons, and so on.
The shells are arranged around the nucleus, and electrons occupy the shells starting from the one closest to the nucleus. The outermost shell is called the valence shell, and the electrons in this shell are involved in chemical reactions.
12
Q
what is the valence electrons
A
Valence electrons are the electrons found in the outermost shell (energy level) of an atom. These electrons are the ones involved in forming chemical bonds with other atoms.
The number of valence electrons determines an element’s chemical properties and how it reacts with other elements. For example:
Sodium (Na) has 1 valence electron (in its outer shell), so it tends to lose that electron easily when it reacts.
Oxygen (O) has 6 valence electrons and tends to gain or share 2 electrons to fill its outer shell.
The number of valence electrons is also related to the element’s position in the periodic table.
13
Q
what is a proton
A
A proton is a positively charged particle found in the nucleus (center) of an atom. Protons, along with neutrons, make up the atom’s mass.
Protons have a positive charge (+1).
The number of protons in an atom determines the element’s atomic number and what element it is. For example, if an atom has 1 proton, it’s hydrogen, and if it has 6 protons, it’s carbon.
14
Q
orbital definition
A
An orbital is a region around the nucleus of an atom where electrons are likely to be found. It describes the probable location of an electron within an atom.
There are different types of orbitals (like s, p, d, f), and each can hold a specific number of electrons. For example:
s orbitals can hold up to 2 electrons.
p orbitals can hold up to 6 electrons.
Orbitals are arranged in layers or shells around the nucleus, with each shell containing different types of orbitals
In chemistry, s, p, d, and f refer to types of orbitals (regions where electrons are likely to be found) that are organized based on their shape and energy levels. Here’s a breakdown:
s orbital:
Shape: Spherical (round).
Can hold up to 2 electrons.
Found in every energy level (shell).
p orbital:
Shape: Dumbbell-shaped.
Can hold up to 6 electrons (there are 3 p orbitals in each energy level).
Found in energy levels starting from the second shell.
d orbital:
Shape: More complex (like cloverleaf or double dumbbells).
Can hold up to 10 electrons (there are 5 d orbitals in each energy level).
Found in energy levels starting from the third shell.
f orbital:
Shape: Even more complex (like double cloverleaf).
Can hold up to 14 electrons (there are 7 f orbitals in each energy level).
Found in energy levels starting from the fourth shell.
These orbitals are part of the electron configuration that helps describe how electrons are arranged in atoms.
15
Q
where can you find the nucleus
A
The nucleus is the small, dense center of an atom. It contains most of the atom’s mass and is located at the very core of the atom. The nucleus is made up of protons (positively charged particles) and neutrons (neutral particles).
The electrons (negatively charged particles) move around the nucleus in regions called electron shells or orbitals. The nucleus is very tiny compared to the overall size of the atom, but it holds almost all the atom’s mass.
16
Q
where can you find the mass number and where is it located
A
The mass number is the total number of protons and neutrons in an atom’s nucleus.
You can usually find the mass number listed on the periodic table next to the element’s atomic number. However, the mass number itself is not always written directly on the table. Instead, it’s calculated by adding the number of protons and neutrons together for a specific isotope of the element.
For example:
Carbon-12 has a mass number of 12 (6 protons + 6 neutrons).
Carbon-14 has a mass number of 14 (6 protons + 8 neutrons).
The atomic number, which tells you the number of protons, is generally found directly below the element’s symbol on the periodic table, while the mass number is often shown as the whole number next to the symbol (or written as the “A” value in isotopic notation).
17
Q
what is a molecule
A
A molecule is the smallest unit of a chemical compound that retains all its chemical properties. It is made up of two or more atoms bonded together through chemical bonds, such as covalent bonds.
For example:
Water (H₂O): A molecule made of two hydrogen atoms and one oxygen atom.
Oxygen (O₂): A molecule consisting of two oxygen atoms bonded together.
Molecules can be simple (like H₂ or O₂) or complex (like proteins or DNA).
18
Q
What is a neutron
A
A neutron is a subatomic particle found in the nucleus of an atom. It has no electric charge, meaning it is neutral.
Neutrons, along with protons, make up the nucleus of an atom. The number of neutrons in an atom can vary, even for atoms of the same element. This creates different isotopes of the element.
For example:
Carbon-12 has 6 protons and 6 neutrons.
Carbon-14 has 6 protons and 8 neutrons.
Neutrons help add mass to the atom but do not affect its chemical behavior, which is determined by the number of protons and electrons.
19
Q
what are subatomic particles, how many are there present in chemical elements and what are they
A
Subatomic particles are the tiny particles that make up an atom. There are three main types of subatomic particles:
Protons:
Found in the nucleus (center) of the atom.
Have a positive charge (+).
The number of protons in an atom determines its element and atomic number.
Neutrons:
Also found in the nucleus.
Have no charge (neutral).
Neutrons, together with protons, contribute to the mass number of the atom.
The number of neutrons can vary in atoms of the same element, creating different isotopes.
Electrons:
Found outside the nucleus, in the electron cloud (orbital).
Have a negative charge (-).
Electrons balance the positive charge of protons to make the atom neutral (if the atom has no charge).
In summary:
Protons and neutrons are found in the nucleus, while electrons orbit around it.
The number of protons defines the element, while electrons affect chemical behavior.
The number of neutrons can vary, creating isotopes of an element.
20
Q
what is the charge of a neutron
A
neutral
21
Q
what is the charge of a proton
A
positive
22
Q
what is the charge of an electron
A
negative
23
Q
is a cation positive or negative
A
positive
24
Q
is an anion positive or negative
A
negative
25
where are electrons found
in shells that surround the nucleus of an atom
26
where are protons found
nucleus
27
where are neutrons found
nucleus
28
do subatomic particles differ in masses?
Yes, subatomic particles differ in mass:
1. Protons and neutrons have similar masses, but neutrons are slightly heavier.
Proton mass ≈ kilograms.
Neutron mass ≈ kilograms.
2. Electrons are much lighter than protons and neutrons.
Electron mass ≈ kilograms, which is about 1/1836 the mass of a proton.
This difference in mass affects the structure and properties of atoms. For example, most of an atom's mass comes from its protons and neutrons, while electrons contribute very little to the overall mass.
29
what two have the same mass? Neutrons, electrons, protons
The neutrons and protons have nearly the same mass.
Neutrons and protons both have a mass of approximately 1 atomic mass unit (amu).
Electrons, on the other hand, have a much smaller mass—about 1/1836 of a proton or neutron.
So, neutrons and protons have almost the same mass, while electrons are much lighter.
30
a proton or a neutron has a mass eqivalent to about how many electrons
1830
31
what are inside the nucleus
protons and neutrons
32
how big is the nucleus is comparison to the size of the atom
tiny
33
True or False: Because they are held within the nucleus, protons and neutrons do not take part in chemical reactions.
true.
34
what orbits the nucleus
electrons
35
do electrons participate in chemical reactions
yes?
36
what is the relative mass of an electron
1
37
what is the relative mass of a proton
1830
38
what is the relative mass of a neutron
1830
39
what does it mean by relative mass
Relative mass refers to the mass of an atom or particle compared to the mass of a standard reference, typically the mass of a carbon-12 atom.
For example:
The relative mass of a proton or neutron is 1 (since they are roughly the same mass).
The relative mass of an electron is much smaller, about 1/1836 of a proton or neutron.
The relative mass doesn't use actual units like grams, but instead compares the mass of different particles relative to each other. So when you say an atom has a relative mass of 12, it means it's 12 times heavier than a carbon-12 atom.
40
True or False: Each atom has only one kind of atom
true
41
do each of these atoms posess the same number of protons
yes
42
True or False, each of these atoms posess the same number of protons but may have a different number of neutrons
true
43
what determines the element? protons electrons or neutrons
protons
44
each shell can hold a maximum number of electrons. once a shell is full, electrons begin to fill the next, higher energy shell. How many electrons can the 1st, 2nd, and 3rd shell hold?
1st can hold 2 electrons
2nd holds 8
3rd holds 18
45
the number of electrons in an atom and which shells they occupy determines what
the chemical reactivity of the atom
46
electronic structure: the valence electrons increase by ?? moving along a period left to right
1
47
electronic structure: moving down one more shell is added, but the valence shells..
remain the same
Moving down a group in the periodic table, one more electron shell (or energy level) is added for each element. However, the valence shell (the outermost shell) remains the same in terms of the number of electrons for elements in the same group.
For example:
Group 1 elements (like lithium, sodium, and potassium) all have 1 valence electron, even though they have different numbers of inner shells:
Lithium (2,1)
Sodium (2,8,1)
Potassium (2,8,8,1)
The addition of shells moving down the group makes the atoms larger and the valence electrons further from the nucleus, which reduces the attraction between the nucleus and the valence electrons. This is why reactivity increases for metals as you move down a group, such as in Group 1.
48
electronic structure: what does a metal lose when the metals (on the left) react with the non metals (on the right) and why
it loses an electron (s) to obtain an electronic arrangement the same as the noble gas nearest to it
49
what is are noble gases
any of the gaseous elements helium, neon, argon, krypton, xenon, and radon, occupying Group (18) of the periodic table.
50
elctronic structure: when a non metal (on the right) react with a metal (on the left) it gains or loses an electron and why
gains an electron to obtain an electronic arrangement the same as the noble has nearest to i
When a non-metal (on the right side of the periodic table) reacts with a metal (on the left side), the non-metal gains electrons. This happens because:
Non-metals have high electronegativity, meaning they strongly attract electrons to fill their outer electron shells and become stable.
Metals, on the other hand, have low electronegativity and tend to lose electrons to achieve stability, usually by emptying their outermost shell.
For example:
Sodium (a metal) loses one electron to become .
Chlorine (a non-metal) gains this electron to become .
This transfer of electrons creates oppositely charged ions that attract each other, forming an ionic bond.
51
for an atom to be electrically neutral, there must be an equal number of what
protons and electrons
52
what leads to an imbalance in the number of protons and electrons
when atoms react and gain or lose electrons
53
what is a net charge
net charge is the total charge of an object, taking into account both positive and negative charges.
the net charge just tells you whether the atom is positive, negative, or neutral overall.
54
Rephrase this "an imbalance in the number of protons and electrons lead to a net charge on the atom which is then an ion."
When an atom has more or fewer electrons than protons, it gets a charge and becomes an ion.
55
fewer electrons than protons lead to a net positive charge and the ion is called a what
cation
56
more electrons than protons lead to a net negative charge and the ion is called a what
anion
57
Is it possible for two or more atoms to have the same number of protons but different numbers of neutrons?
Yes, this is possible. Atoms like this are called isotopes. They are the same element because they have the same number of protons, but they have different masses due to the different numbers of neutrons.
58
for hydrogen, each isotope has its own special name, but they can also be called by their mass numbers. For example:
Hydrogen-1 (no neutrons) is called protium.
Hydrogen-2 (1 neutron) is called deuterium.
Hydrogen-3 (2 neutrons) is called tritium.
in such caes these atoms are isotopes of the same element
Question: What are the names of the hydrogen isotopes, and how do they relate to their mass numbers?
he hydrogen isotopes are:
Protium (Hydrogen-1): It has no neutrons.
Deuterium (Hydrogen-2): It has 1 neutron.
Tritium (Hydrogen-3): It has 2 neutrons.
The numbers (1, 2, and 3) come from the total of protons and neutrons in the nucleus, which is the mass number.
Neutrons = Mass number - Number of protons
Example:
For Hydrogen-2 (Deuterium):
Mass number = 2
Protons = 1 (since hydrogen always has 1 proton)
Neutrons = 2 - 1 = 1
So, Deuterium has 1 neutron.
59
Why do all isotopes of the same element behave the same way in chemical reactions?
Because it is the number of protons which determines the chemical properties of an atom, all isotopes of a particular element will all behave the same way in chemical reactions
and isotopes of an element always have the same number of protons. The difference in neutrons does not affect how they react chemically.
60
how do you write an isotope symbol?
you write the element symbol, the mass number in small on the top left and the atomic number beaneath the mass number
61
info breakdown
Elements are made up of a mix of different isotopes, and because of this, the atomic mass of an element is the average of the isotopes, taking into account how common each isotope is
So, if an element has a lot of one isotope and only a little of another, the atomic mass will be closer to the mass of the more common isotope.
For example, carbon has mainly two isotopes: carbon-12 and carbon-14. The atomic mass is an average of these two, based on how much of each isotope is found in nature.
* Elements are made of different isotopes (atoms of the same element but with different numbers of neutrons).
* The atomic mass of an element isn't just the mass of one isotope. It's an average of all the isotopes of that element.
*This average takes into account how much of each isotope is present (called percent abundance).
62
info breakdown
Chlorine is made of two isotopes: chlorine-35 and chlorine-37. In nature, 75% of chlorine is chlorine-35, and 25% is chlorine-37. The average atomic mass of chlorine is calculated by multiplying the mass of each isotope by its percentage and then adding them up:
Atomic mass = (0.75 × 35) + (0.25 × 37) = 35.5
This average value (35.5) is shown in the periodic table for chlorine. The same method is used for other elements if we know the percentages of their isotopes.
Isotopic composition means the specific amounts or percentages of each isotope of an element.
63
why is the nucleus positively charged
The nucleus is positively charged because it contains protons, which have a positive charge.
Neutrons, also in the nucleus, have no charge (neutral), so they don't affect the overall charge.
64
explain why the nucleus contains most of the mass of the atom
The nucleus contains most of the mass of an atom because it holds the protons and neutrons, which are much heavier than the electrons. Protons and neutrons are about 1,800 times heavier than electrons, so most of the atom's mass comes from the nucleus.
65
explain why electrons are attracted to the nucleus
Electrons are attracted to the nucleus because the protons in the nucleus have a positive charge, and electrons have a negative charge. Opposite charges attract, so the negative electrons are pulled towards the positive protons in the nucleus.
66
explain why the atom may be considered mostly space
An atom is mostly empty space because the nucleus (which contains protons and neutrons) is tiny compared to the overall size of the atom, and the electrons are located far away from the nucleus in "orbitals." The electrons are very small and spread out, so most of the atom is just empty space between the nucleus and the electrons.
67
neutral atoms (not ions): how do you figure out the atomic number, number of electrons and protons?
neutral atoms (not ions): the atomic number, number of electrons and protons are all the same
the atomic number is top number in the periodic table
68
in neutral atoms how to you find the mass number
protons + neutrons + mass number
the mass number is also located on the bottom of the element on the periodic table
69
for an ion how do you find the atomic number
the top number on the periodic table.
70
for an ion how do you find how many protons there are
it is the same number as the atomic number. look at the top number above the element in the periodic table. this is the same as a neutral atom
71
the number of electrons depend on the charge
for an ion how do you find how many electrons there are
positive charge (cation): fewer electrons than protons
negative charge (anion) more elctrons than protons
Example: Na+ (atomic number 11) has 11 protons but only 10 electrons
To find the number of electrons in an ion, start with the number of protons (which is the atomic number).
you can find the number of electrons by assuming the atom is neutral (if you don't know the charge of the atom) In a neutral atom, the number of electrons equals the number of protons.
If the ion has a positive charge (cation), subtract the charge from the number of protons.
If the ion has a negative charge (anion), add the charge to the number of protons.
For example:
Na⁺ (sodium ion with a +1 charge): 11 protons - 1 = 10 electrons.
Cl⁻ (chlorine ion with a -1 charge): 17 protons + 1 = 18 electrons.
72
if no charge is indicated assume the atom is neutral therefore it is not an
it is not an ion if it is neutral
73
how to atoms become ions
when they gain or lose electrons to achieve a stable configuration (usually a full outer shell)
74
metal atoms (like Na, Mg, Al) tend to lose electrons which form...
positive ions, Cations
example: Sodium (Na) loses 1 electron and becomes Na+
example: Magnesium (Mg) loses 2 electrons and becomes Mg2+
75
non metal atoms (like Cl, O, N) tend to gain electrons which form...
negative ions, Anions
example: Chlorine (Cl) gains one electron which becomes Cl-
example: Oxygen (O) gains two electrons which becomes O2-
76
chemical reactions: ions are often formed during what
chemical reactions,
example: NaCl (sodium chloride) dissolves/dissociates into Na+ (sodium ion) and Cl- (chloride ion) in water
Here’s why:
Water molecules are polar: Water has a positive end (hydrogen side) and a negative end (oxygen side). This means water can attract and surround charged particles, like the Na⁺ and Cl⁻ ions.
Dissociation process:
NaCl is made of Na⁺ (positively charged sodium) and Cl⁻ (negatively charged chloride) ions held together by ionic bonds.
When NaCl is placed in water, the water molecules surround and break apart the ions because of their opposite charges. The Na⁺ ions are attracted to the negative oxygen side of water molecules, and the Cl⁻ ions are attracted to the positive hydrogen side.
As a result, NaCl dissociates into Na⁺ and Cl⁻ ions, making the solution conductive and allowing the ions to move freely in the water.
77
metals (left side of the periodic table) form positive ions (cations)
non metals on the right side of the periodic table form negative ions (anions)
78
how do you find the mass number for an ion
protons + neutrons
it is the same as a neutral atom. It is located on the bottom of the element on the periodic table
79
how do you find how many neutrons there are for an ion
mass number - atomic number
80
how do you calculate the average atomic mass for isotopes
for each isotope, multiply its 'weight' by how much it 'counts' (percentage as a decimal ) then add those numbers up to get the average atomic mass.
81
calculating atomic mass for isotope examples:
A. Lithium
Lithium has 2 isotopes lithium-6 and lithium-7, with the percentage abundance of 7.5% and 92.5% respectively
Lithium-6: weight = 6, counts 7.5% (or 0.075)
Lithium-7: weight = 7, counts 92.5% (or 0.925)
average weight = (6x0.075) + (7x0.925) = 0.45+6.475 = 6.98
82
calculating atomic mass for isotope examples:
B. Magnesium
Magnesium has three isotopes Magnesium-24, Magnesium-25, and Magnesium-26 with the percentage abundance of 79%, 10%, and 11% respectively
Magnesium-24: weight = 24, counts 79% (0.79)
Magnesium-25: weight = 25, counts 10% (0.10)
Magnesium-26: weight= 26, counts 11% (0.11)
Average weight = (24x0.79) + (25x0.10) + (26x0.11) = 18.96 + 2.5 + 2.86 = 24.32
83
calculating atomic mass for isotope examples:
C. Nickel
Nickel has five isotopes nickel-58, nickel-60, nickel-61, nickel-62, and nickel-64, with the percentage abundance of 68.1%, 26.2%, 1.2%, 3.6%, and 0.9% respectively
Average weight = (58x0.681) + (60x0.262) + (61x0.012) + (62x0.036) + (64x0.009)
= 39.498 + 15.72 + 0.732 + 2.232 + 0.576 = 58.76
nickels average weight is about 58.76
84
How many electrons are there in sr2+ ?
36.
Find the number of protons:
The atomic number of strontium (Sr) is 38, so Sr has 38 protons.
Determine the charge:
The Sr²⁺ ion has a +2 charge, which means it has lost 2 electrons.
Find the number of electrons:
In a neutral Sr atom, there would be 38 electrons (the same as the number of protons).
Since Sr²⁺ has lost 2 electrons, the number of electrons in Sr²⁺ is:
38 protons - 2 electrons = 36 electrons
85
what single word ( anions, cations, or isotopes) - can be used to fully describe these two particles?
Particle X contains 17 protons, 18 neutrons and 18 electrons.
Particle Y contains 16 protons, 18 neutrons, and 18 electrons.
what word can be used to describe these two particles
anion.
Here’s why:
Particle X has 17 protons and 18 electrons, so it has a negative charge (since it has more electrons than protons). It is an anion.
Particle Y has 16 protons and 18 electrons, so it also has a negative charge (since it has more electrons than protons). It is also an anion.
However, both particles are ions because they have a charge (due to the difference between protons and electrons).
86
explain why the atomic mass of chlorine is 35.5
The atomic mass of chlorine is 35.5 because chlorine is made of two isotopes: chlorine-35 (75%) and chlorine-37 (25%). The atomic mass is an average of their masses, taking into account how much of each isotope is present.
87
elements are pure substances made up of only one type of atom.
in the periodic table the elements in order of atomic number (number of protons in the nucleus of the atom)
the staircase on the right hand side of the table separates the metals from the non metals.
metals are to the left below the staircase. non metals are to the right and above the staircase.
elements adjacent to the staircase can display both metallic and non metallic properties. these are called metalloids.
88
what are groups in the periodic table
these are vertical columns. labelled group 1-18. a group contains elements with similar chemical properties because all the elements in a gorup have the same number of valence electrons and these electrons determine the chemical properties of an element
89
Group 1 - Alkali Metals
Lithium (Li), Sodium (Na), potassium (K), rubidium (Rb), Caesium (Cs) and francium (Fr) are all..
* silvery-white coloured.
* Metals
* relatively low melting points
* reactivity increases down the group
90
alkali metals react with what to produce what
alkali metals react with water to produce hydrogen gas and heat. the heat produced can ignite (burn) the hydrogen gas produced.
As you move down the gorup, the reactions become quicker. the general equation for the reaction of an alkali metal with water is below, just replace M with the elements symbol.
2M + 2H2O -> 2MOH + H2
91
Group 2 - Alkaline Earth metals.
Beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba) and radium (Ra) are all:
* Silvery-white coloured
* metals
* high melting points
* reactivity increases down the group
they react with water to produce hydrogen gas and heat
the reactions are slower than group 1 elements
92
Alkali metals are in what group
1
93
alkaline earth metals are in what group
2
94
what do alkaline earth metals react with and what do they produce
they react with water to produce hydrogen gas and heat
95
group 17 - halogens
Florine (F), Chlorine (Cl), Bromine (Br), Iodine (I), and Astatine (At):
Halogens form diatomic molecules (Diatomic means a molecule made of two atoms bonded together. Examples are oxygen (O₂) and hydrogen (H₂) )
*are very reactive metals
*reactivity decreases down the group
*F2 and Cl2 are pale green gases
*Br2 is a redbrown liquid
*I2 is a violet solid
96
what colour is Br2
redbrown liquid
97
what colour is F2 and Cl2
Pale green gases
98
what colour is I2
Violet solid
99
is F2 and Cl2 a gas, liquid or solid
gas
100
is Br2 a gas, liquid or solid
liquid
101
is I2 a gas, liquid or solid
solid
102
what group are halogens in
17
103
are halogens reactive with metals
yes very
104
does reactivity increase or decrease down the halogens group
reactivity decreases
105
do alkaline earth metals have a high or low melting point
high melting point
106
do alkali metals have a high or low melting point
relatively low
107
what colour are alkaline earth metals
silbvery-white coloured
108
what colour are alkali metals
silvery-white coloured
109
does reactivity increase or decrease as in goes down ( in the alkali metals group
reactivity increases down the group
110
group 18 - Noble gases
Helium (He), neon (Ne), argon (Ar), Krypton (Kr), Xenon (Xe), and radon (Rn):
* the last group discovered
*all found naturally in the atmosphere (except radon)
*essentially unreactive
111
what group are nobel gases in?
18
112
how reactive are nobel gases
esentialy unreactive
113
where are nobel gases found
all naturally in the atmosphere except radon
(Radon is not found naturally in the atmosphere like other noble gases because it is radioactive and unstable, meaning it decays quickly into other elements. It is produced in the Earth’s crust from the radioactive decay of uranium and thorium in rocks and soil, so it is found in the ground instead of remaining in the atmosphere.)
114
what was the last group in the periodic table that was discovered
nobel gases
115
what are periods in the periodic table
these are horizontal rows of the periodic table. moving along a period i.e. from left, to right, there is a change in the type of element, i.e. from metals to metalloids.
116
do groups go up or down
down
117
do periods go left to right or down
left to right. horizontally
118
when group 1 (alkali metals) elements react with water, each of their atoms loses an electron from its valence shell.
for sodium and potassium, these processes can be represented by the equations Na -> Na+ + e- K -> K+ + e-
Explain, by referring to the electron configurations of sodium and potassium, why potassium is more reactive than sodium.
* Sodium’s electron configuration: 2, 8, 1
* Potassium’s electron configuration: 2, 8, 8, 1
Potassium is more reactive than sodium because its outer electron is further away from the nucleus.
Sodium’s electron configuration: 2, 8, 1 (outer electron is in the 3rd shell).
Potassium’s electron configuration: 2, 8, 8, 1 (outer electron is in the 4th shell).
Since potassium's outer electron is farther from the nucleus, the pull from the nucleus is weaker, making it easier to lose the outer electron. This is why potassium reacts more quickly with water than sodium.
119
a teacher added a small piece of sodium to a trough containing water. give two observaions you would make
1. Fizzling or bubbling: This happens because hydrogen gas is released during the reaction.
2. Sodium moves around on the water surface: The reaction generates heat, causing the sodium to melt and dart around.
(sodium continues to dart around on the surface of the water even after it melts. This happens because the reaction between sodium and water releases hydrogen gas, which pushes the sodium across the surface like a tiny boat. The heat from the reaction keeps it in a liquid state while it moves.)
120
in another experiment the teacher added a small piece of a different group 1 element and noticed that the element was less vigorous. which element did she add out of the 3 options (Li, Na, and K)
* Lithium’s electron configuration: 2, 1 (outer electron in the 2nd shell).
* Sodium’s electron configuration: 2, 8, 1 (outer electron in the 3rd shell).
* Potassium’s electron configuration: 2, 8, 8, 1 (outer electron in the 4th shell).
The teacher added lithium (Li).
Why: Lithium is the least reactive of the three (Li, Na, K) because its outer electron is closer to the nucleus. The closer the electron is, the stronger the pull from the nucleus, making it harder to lose the electron. This means lithium reacts less vigorously with water compared to sodium and potassium.
121
write the balanced chemical equation for the reaction between potassium and water.
Key Tip:
When group 1 elements react with water:
* Always expect a hydroxide (like KOH) and hydrogen gas (H₂) as the products.
* Then balance the equation using the number of atoms for each element.
Balanced Chemical Equation:
2K + 2H₂O → 2KOH + H₂
1. Understand the reaction:
* Potassium (K) reacts with water (H₂O). From basic chemistry, you know:
Group 1 elements (like K) react with water to produce a hydroxide (KOH) and hydrogen gas (H₂).
2. Write the unbalanced equation:
* Start with the reactants and products you know:
K + H₂O → KOH + H₂
3. Balance the equation step-by-step:
* Potassium (K):
There's 1 K on the left and 1 K in KOH on the right, so potassium is balanced.
* Hydrogen (H):
On the left, H₂O has 2 hydrogen atoms. On the right, KOH has 1 hydrogen, and H₂ adds 2 more. To balance, you need 2 H₂O on the left and 2 KOH on the right.
* Oxygen (O):
Now check oxygen. With 2 H₂O molecules on the left, there are 2 oxygen atoms. On the right, 2 KOH also has 2 oxygen atoms, so oxygen is balanced.
4. Final balanced equation:
Once everything is balanced, the equation becomes:
2K + 2H₂O → 2KOH + H₂
122
which information shows that the elements have similar chemical properties?
Element: Li
*Atomic number: 3
*atomic mass: 6.9
*electronic configuration: 2.1
*density (g cm-3) 0.53
*melting point (°C) 180
Element: Na
*Atomic number: 11
*atomic mass: 23.0
*electronic configuration: 2.8.1
*density (g cm-3) 0.97
*melting point (°C) 98
Element: K
*Atomic number: 19
*atomic mass: 39.1
*electronic configuration: 2.8.8.1
*density (g cm-3) 0.86
*melting point (°C) 64
All three elements have one electron in their outer shell, which means they are in Group 1 of the periodic table. This common feature gives them similar chemical behavior, such as reacting with water in a similar way.
The density and melting points may differ, but these are physical properties, and the key to their similar chemical properties is their electronic configuration.
123
the elements in group 1 show a clear trend in their chemical properties. indentify the physical property that shows a clear trend.
Element: Li
*Atomic number: 3
*atomic mass: 6.9
*electronic configuration: 2.1
*density (g cm-3) 0.53
*melting point (°C) 180
Element: Na
*Atomic number: 11
*atomic mass: 23.0
*electronic configuration: 2.8.1
*density (g cm-3) 0.97
*melting point (°C) 98
Element: K
*Atomic number: 19
*atomic mass: 39.1
*electronic configuration: 2.8.8.1
*density (g cm-3) 0.86
*melting point (°C) 64
The melting point is the physical property that shows a clear trend among the elements in Group 1 (alkali metals):
Li: Melting point = 180°C
Na: Melting point = 98°C
K: Melting point = 64°C
As you move down Group 1, the melting points decrease because the atoms get larger, and the forces between their particles (such as metallic bonds) become weaker. This makes the elements less stable and requires less energy to break the bonds, leading to lower melting points.
124
the elements also show a clear trend in their chemical properties, such as their reaction with water.
Name a gas produced when lithium reacts with water and write a balanced chemical equation.
Element: Li
*Atomic number: 3
*atomic mass: 6.9
*electronic configuration: 2.1
*density (g cm-3) 0.53
*melting point (°C) 180
Element: Na
*Atomic number: 11
*atomic mass: 23.0
*electronic configuration: 2.8.1
*density (g cm-3) 0.97
*melting point (°C) 98
Element: K
*Atomic number: 19
*atomic mass: 39.1
*electronic configuration: 2.8.8.1
*density (g cm-3) 0.86
*melting point (°C) 64
When lithium reacts with water, the gas produced is hydrogen (H₂).
The balanced chemical equation for the reaction is:
2Li + 2H₂O → 2LiOH + H₂
In this reaction:
Lithium (Li) reacts with water (H₂O) to form lithium hydroxide (LiOH) and hydrogen gas (H₂).
125
what colour is Fluorine (F) at room temperature
pale yellow gas at room temp
126
what colour is chlorine (Cl) at room temperature
greenish yellow at room temp
When it is in its liquid or solid form, it appears as a pale yellow color.
127
what colour is Bromine (Br) at room temperature
red-brown at room temp
When it evaporates into a gas, it has a reddish-brown color as well.
128
what colour is Iodine (I) at room temperature
Grey.
Iodine is often described as grey or greyish-black in its solid form because of its appearance before it sublimates into a purple vapor. While its color can appear as dark purple or violet when vaporized, in its solid state, it is typically a shiny grey or blackish-grey due to its crystalline form.
Iodine is a dark purple or violet solid at room temperature. When it sublimates (turns into a gas), it forms a purple vapor
129
suggest why each halogen was not added to the solution with the corresponding halide ion.
(A halogen is an element in Group 17 of the periodic table. These elements are fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). Halogens are very reactive and often form salts when they combine with metals.)
(A halide is a compound formed when a halogen (like chlorine, iodine, or fluorine) combines with another element, usually a metal. For example, sodium chloride (NaCl) is a halide made of sodium and chlorine.)
Halogens were not added to the solution with their corresponding halide ions because halogens and halide ions already have a bond or reaction between them. For example:
Chlorine (Cl₂) would not be added to a solution with Cl⁻ because chlorine would react with the chloride ion (Cl⁻), potentially displacing other halogens or changing the solution's composition.
Each halogen is highly reactive, and adding it to a solution with its corresponding halide would not lead to useful reactions and could cause unwanted results.
130
why was there no reaction when iodine was added to the sodium bromide solution
There was no reaction when iodine was added to the sodium bromide solution because iodine (I₂) is less reactive than bromine (Br₂).
Iodine is less reactive than bromine because it is further down the halogen group in the periodic table. The reactivity of halogens decreases as you move down the group.
In a solution of sodium bromide (NaBr), bromine ions (Br⁻) are already present. For a halogen to react and replace another halide ion, the halogen added must be more reactive. Since iodine is less reactive than bromine, it cannot displace the bromine ions from the sodium bromide solution, so no reaction occurs.
131
how do you know which elements have a +1 ion and which have a 1- ion
You can determine which elements form a +1 ion or a -1 ion by looking at their position in the periodic table.
+1 ions:
Elements in Group 1 (the alkali metals), like lithium (Li), sodium (Na), and potassium (K), form +1 ions because they have one electron in their outermost shell, which they easily lose to form a positive charge (cation).
-1 ions:
Elements in Group 17 (the halogens), like fluorine (F), chlorine (Cl), bromine (Br), and iodine (I), form -1 ions because they have seven electrons in their outermost shell and need to gain one more electron to complete their shell, making them negatively charged (anion).
In short:
Group 1 → +1 ions (lose 1 electron).
Group 17 → -1 ions (gain 1 electron).
132
the only group with a full outer shell is what
group 18 the gases
Group 1 (Alkali metals):
These elements have 1 electron in their outer shell, so they don’t have a full outer shell.
Examples: Lithium (Li), Sodium (Na), Potassium (K).
Group 2 (Alkaline earth metals):
These elements have 2 electrons in their outer shell, so they don't have a full outer shell either.
Examples: Magnesium (Mg), Calcium (Ca).
Groups 3-12 (Transition metals):
These elements have varying numbers of electrons in their outer shell, but they typically don’t have full outer shells.
Examples: Iron (Fe), Copper (Cu), Zinc (Zn).
Group 13 (Boron group):
These elements have 3 electrons in their outer shell, so they don’t have a full outer shell.
Examples: Boron (B), Aluminum (Al).
Group 14 (Carbon group):
These elements have 4 electrons in their outer shell, so they don’t have a full outer shell.
Examples: Carbon (C), Silicon (Si).
Group 15 (Nitrogen group):
These elements have 5 electrons in their outer shell, so they don’t have a full outer shell.
Examples: Nitrogen (N), Phosphorus (P).
Group 16 (Oxygen group):
These elements have 6 electrons in their outer shell, so they don’t have a full outer shell.
Examples: Oxygen (O), Sulfur (S).
Group 17 (Halogens):
These elements have 7 electrons in their outer shell, so they don’t have a full outer shell, but they are 1 electron short of being stable.
Examples: Fluorine (F), Chlorine (Cl), Bromine (Br).
The only Groups with full outer shells are:
Group 18 (Noble gases): These elements have 8 electrons in their outer shell (except Helium, which has 2) and are chemically stable.
Examples: Helium (He), Neon (Ne), Argon (Ar).
133
what is a monatomic atom
A single atom is just one atom on its own, not bonded to any other atoms. It is a single piece of an element, not part of a molecule or compound.
Monatomic means that the element exists as individual atoms, not as groups of atoms bonded together. "Mono" means one, so monatomic just means one atom.
For example:
Noble gases like Helium (He) and Neon (Ne) are monatomic because they exist as single, separate atoms, not connected to other atoms.
134
looking at the periodic table, what is the atomic number of magnesium
12
135
out of these 4, how many protons does an atom of oxygen have
hydrogen
mass number: 1
atomic number: 1
Oxygen
mass number: 16
atomic number: 8
Magnesium
mass number: 24
atomic number: 12
Argon
mass number: 40
atomic number: 18
8
136
out of these 4, name the element that does not react with any of the others. explain your answer
hydrogen
mass number: 1
atomic number: 1
Oxygen
mass number: 16
atomic number: 8
Magnesium
mass number: 24
atomic number: 12
Argon
mass number: 40
atomic number: 18
Argon.
because it is stable. (full valence shell)
137
out of these 4, name the pair of elements that combine to form an ionic compound.
hydrogen
mass number: 1
atomic number: 1
Oxygen
mass number: 16
atomic number: 8
Magnesium
mass number: 24
atomic number: 12
Argon
mass number: 40
atomic number: 18
Magnesium and Oxygen
(cation + anion) (metal+non metal)
Ionic compounds are formed when a cation (positive ion) and an anion (negative ion) combine, and this often happens when a metal reacts with a non-metal.
Magnesium Oxide (MgO) is an ionic compound formed by the combination of Magnesium and Oxygen.
138
out of the 4, state and explain which of the symbols above shows an atom that does not contain any neutrons
hydrogen
mass number: 1
atomic number: 1
Oxygen
mass number: 16
atomic number: 8
Magnesium
mass number: 24
atomic number: 12
Argon
mass number: 40
atomic number: 18
hydrogen.
because the mass number and the atomic number is the same.
Hydrogen has an atomic number of 1, meaning it has 1 proton in its nucleus.
The mass number of an atom is the total number of protons and neutrons in its nucleus.
For Hydrogen:
Mass number = 1
Since Hydrogen has 1 proton (because the atomic number is 1), the mass number tells us how many total particles are in the nucleus (protons + neutrons).
So, for Hydrogen, the mass number is 1, and since we already know there is 1 proton, there must be 0 neutrons because the mass number is the sum of protons and neutrons.
Thus, Hydrogen does not contain any neutrons in its most common form (called protium).
139
protium meaning
Protium (the most common form):
1 proton, 0 neutrons, 1 electron.
Protium is just the name for the most common form of hydrogen.
It is a hydrogen atom that has:
1 proton (in the nucleus),
0 neutrons, and
1 electron (outside the nucleus).
So, protium is simply hydrogen with no neutrons in its nucleus. It's the most common type of hydrogen found in nature.
140
Deuterium meaning
Deuterium:
1 proton, 1 neutron, 1 electron (this is a heavier form of hydrogen).
There is only one type of deuterium.
Deuterium is a isotope of hydrogen with:
1 proton
1 neutron
1 electron
Deuterium is a heavier form of hydrogen, and it is sometimes called "heavy hydrogen" because it has one neutron in addition to the proton that all hydrogen atoms have. Deuterium is found naturally in small amounts, about 0.015% of all hydrogen on Earth.
141
Tritium meaning
1 proton, 2 neutrons, 1 electron (this is a radioactive form of hydrogen).
There is only one type of tritium.
Tritium is another isotope of hydrogen, and it has:
1 proton
2 neutrons
1 electron
Tritium is a radioactive form of hydrogen and is much rarer than deuterium. It decays over time and is used in some special applications, like in certain types of nuclear reactions or glow-in-the-dark materials. However, it doesn't naturally occur in large quantities on Earth.
142
The three isotopes — protium, deuterium, and tritium are unique to which element
are unique to hydrogen.
143
what does Diatomic mean
Diatomic means that a molecule is made up of two atoms.
For example:
Oxygen (O₂) is diatomic because it consists of two oxygen atoms bonded together.
Hydrogen (H₂) is diatomic because it consists of two hydrogen atoms bonded together.
Diatomic molecules can be made of two atoms of the same element (like O₂ or H₂), or two atoms of different elements (like CO, carbon monoxide).
144
how many diatomic elements are there
7
The seven diatomic elements are:
H for Hydrogen (H₂)
N for Nitrogen (N₂)
F for Fluorine (F₂)
O for Oxygen (O₂)
I for Iodine (I₂)
C for Chlorine (Cl₂)
B for Bromine (Br₂)
A simple way to remember them is by
"Have No Fear Of Ice Cold Beer"
H for Hydrogen (H₂)
N for Nitrogen (N₂)
F for Fluorine (F₂)
O for Oxygen (O₂)
I for Iodine (I₂)
C for Chlorine (Cl₂)
B for Bromine (Br₂)
These elements are diatomic because, under normal conditions, they pair up to form stable molecules with two atoms. Other elements, like metals or noble gases, do not typically form diatomic molecules.
145
which element out of the listed below is liquid at room temp
*aluminium
*mercury
*nitrogen
*rubidium
*silicon
*xenon
mercury
146
which element below is in group 14 and period 3 of the periodic table?
*aluminium
*mercury
*nitrogen
*rubidium
*silicon
*xenon
silicon
147
which element below has atoms with 8 electrons in their outer shell?
*aluminium
*mercury
*nitrogen
*rubidium
*silicon
*xenon
xenon
beause it is in group 18 which all have stable full shells
148
which element below is a colourless diatomic gas at room temperature
*aluminium
*mercury
*nitrogen
*rubidium
*silicon
*xenon
nitrogen
7 diatomics
H
N
F
O
I
C
Br
(Have No Fear Of Ice Cold Beer)
149
which element below has atoms with only 3 electrons in their outermost shell?
*aluminium
*mercury
*nitrogen
*rubidium
*silicon
*xenon
aluminium
because its in group 13 which all have 3 in their outermost shell
150
which element below reacts violently with water
*aluminium
*mercury
*nitrogen
*rubidium
*silicon
*xenon
rubidium.
alkali metals (group 1) are known for reacting violently with water.
151
alloy meaning
An alloy is a mixture of two or more metals, or a metal and a non-metal, that are combined together to improve the properties of the materials involved.
For example:
Bronze is an alloy made of copper and tin.
Steel is an alloy made of iron and carbon (and sometimes other elements).
Alloys are created to enhance characteristics like strength, durability, corrosion resistance, or conductivity, which individual metals might not have on their own.
152
what does chemical property mean
A chemical property is a characteristic of a substance that describes how it reacts with other substances or changes into a new substance during a chemical reaction.
For example:
Flammability (how easily something can catch fire)
Reactivity with water (like how sodium reacts with water to produce hydrogen gas)
Acidity or basicity (whether a substance is acidic or alkaline)
Chemical properties can't be observed just by looking at a substance; you have to perform a chemical reaction to see them in action.
153
what does conductivity mean
Conductivity refers to how well a material can carry electric current or heat.
Electrical conductivity is how well a material allows electricity to pass through it. For example, metals like copper and aluminum have high electrical conductivity, meaning they let electricity flow easily.
Thermal conductivity is how well a material allows heat to flow through it. For example, metals like copper and silver also have high thermal conductivity, meaning they transfer heat efficiently.
In short, conductivity describes how well a material can conduct or transmit energy (either electrical or thermal).
154
what is corrosion
Corrosion is the process by which metals gradually break down or deteriorate due to chemical reactions with their environment, usually with oxygen or water.
The most common example is rusting, which happens when iron reacts with oxygen and water to form iron oxide (rust). This weakens the metal over time.
Corrosion can damage metals and affect their appearance, strength, and functionality, which is why it's important to protect metals (like with paint or coatings) to prevent it.
155
what is density
Density is a measure of how compact or concentrated the matter in a substance is. It tells you how much mass is packed into a certain volume.
The formula for density is:
Density = Mass÷Volume
In simple terms:
Mass is how much matter (stuff) is in an object.
Volume is how much space the object occupies.
For example, if you have two objects with the same size (volume), but one is heavier, the heavier one has a higher density.
For water, the density is about 1 g/cm³. If something has a density less than 1 g/cm³, it will float in water; if it’s more, it will sink.
156
what does ductility mean
Ductility is the ability of a material, usually a metal, to be stretched or pulled into a thin wire without breaking.
In simple terms, ductility describes how flexible or malleable a material is when it is pulled or drawn out.
For example:
Copper is highly ductile, which is why it is used to make electrical wires.
Gold is also ductile and can be made into thin sheets or wires.
The more ductile a material is, the easier it is to shape it without it snapping or cracking.
157
what does lustre mean
Lustre refers to how shiny or reflective a surface is. It describes the way light interacts with the surface of a material, making it appear shiny or dull.
For example:
Metals like gold, silver, and copper have a high lustre, meaning they are shiny and reflect light well.
Non-metals like wood or rubber usually have low lustre, meaning they don't shine much and are more dull in appearance.
In short, lustre tells us how glossy or shiny something looks.
158
what does malleability mean
Malleability is the ability of a material, usually a metal, to be hammered, pressed, or rolled into thin sheets without breaking or cracking.
In simple terms, malleability describes how easily a material can be shaped or flattened.
For example:
Gold is highly malleable, which is why it can be hammered into very thin sheets (like gold leaf).
Aluminum is also malleable and is used to make things like aluminum foil.
The more malleable a material is, the easier it is to shape it by hammering or pressing it.
159
what does ore mean
Ores are rocks that contain valuable metals or minerals that can be extracted. These metals are mixed with other elements, but we can separate them through chemical processes.
For example:
Iron ore has iron, which we can get by heating it up.
Copper ore has copper, which can be separated using chemicals.
Basically, ores are rocks that give us useful metals.
160
what does it mean by ' physical property '
A physical property is a characteristic of a substance that can be observed or measured without changing the substance itself.
Examples of physical properties include:
Color
Shape
Size
Density
Melting point
In simple terms, physical properties describe what a substance is like, without changing what the substance is. For example, if you cut a piece of metal, you haven't changed the metal itself; you've just changed its shape.
161
what is rusting
Rusting is a chemical process where iron (or steel) reacts with oxygen from the air and water to form iron oxide (rust). This process slowly damages the metal, making it weaker and flaky.
In simple terms, rusting happens when metal, especially iron, gets wet and exposed to air for a long time, turning it orange-brown and causing it to fall apart over time.
162
what is salt in chemistry
In chemistry, salt is a compound formed when an acid reacts with a base. It is made up of positively charged ions (cations) and negatively charged ions (anions), and it usually forms in the process called neutralization.
For example:
When sodium hydroxide (a base) reacts with hydrochloric acid, it forms sodium chloride (NaCl), which is common table salt.
In simple terms, salt is a substance made from the combination of an acid and a base, like how table salt is made from sodium and chlorine.
163
what is smelting
Smelting is a process used to extract metals from their ores by heating them to a very high temperature. This process helps separate the metal from the other materials in the ore, often using chemicals to help remove unwanted substances.
For example:
Iron ore is heated in a furnace with carbon (coke) to remove oxygen and get pure iron.
In simple terms, smelting is like "cooking" the ore at a very high temperature to get the metal we want.
164
matter recap
* all matter is composed of tiny particles called atoms
* any substance in which all the atoms are of the same type is called an element
* categorising the elements based on their physical and chemical properties leads to two major element types: metals and non metals
* the staircase on the right hand side of the table separates the metals from the non metals
* metals are to the left and below the staircase. non metals are to the right and above the staircase
* elements adjacent to the staircase can display both metallic and non metallic properties and are called metalloids. metals are on the left if the periodic table, and non metals are on the right
165
9 common metals in no particular order:
Metal: Copper
Symbol: Cu
Appearance: A bright, heavy, reddish metal
Metal: Gold
Symbol: Au
Appearance: a soft, heavy, bright yellow metal
Metal: Silver
Symbol: Ag
Appearance: a soft, bright, silvery metal
Metal: Iron
Symbol: Fe
Appearance: a strong, silvery-grey, heavy metal
9 common metals cont:
Metal: Lead
Symbol: Pb
Appearance: A bluish-white, soft, heavy metal
Metal: Zinc
Symbol: Zn
Apperance: A bluish-white, brittle metal
Metal: Mercury
Symbol: Hg
Appearance: a heavy, silvery-white, brittle metal
Metal: Magnesium
Symbol: Mg
Appearance: a silvery-
white, light metal
Metal: Aluminium
Symbol: Al
Appearance: a strong, light, silvery-white metal
166
metals and their physical properties
most people, when faced with a new material; can quickly identify it as being metal, or non metal.
when you look at the material, you are analysing the physical properties (e.g. colour, density, lustre) , and based on these observations, classifying it as metal or not.
This can be done because all metallic elements have common properties, which are significantly difference from those non metals
Physical properties
*State (solid, liquid or gas:
nearly all are solid, except mercury
*Melting point (temperature): all have high MPs (above 300 °C) except mercury
*Colour: most are silvery-white, except copper and gold
*Density (mass per unit volume): most are dense but aluminium and magnesium are fairly light
*Lustre (shininess): all are shiny when freshly cut
*Strength: most are strong except a few
*Malleability (workability): most can be reshaped readily
*Ductility (stretchability): all metals can be stretched without breaking
*Thermal (heat) conductivity: all are good conductors of heat
*Electrical (current) conductivity: all are good current conductors
167
Physical properties:
State (solid, liquid or gas)
nearly all metals are solid except which metal
mercury.
with a single exception, all metallic elements are solids at room temperature. The exception, mercury, is a liquid under normal conditions
168
Physical properties:
Melting Point (temperature): all metals have high MPs (above 300 °C) except which metal
mercury.
All metals (except mercury) have relatively high melting points, with the metal tungsten having the highest melting point of all the metals (3422°C)
169
Physical properties:
Colour: most metals are silvery-white except for which metals
copper and gold
170
Physical properties:
Density (mass per unit volume): most metals are dense but which metals
aluminium and magnesium are fairly light
171
Physical properties make metals ideal for use in electrical equipment (wires, switches) and structural applications (automotive bodies, soda cans); however, it is often useful to combine molten metas to create an alloy
the alloying process allows for the physical properties of the material to be matched to its inteded use. common alloys include brass (copper and zinc) , stainless steel ( iron, nickel, chromium) , and many coins ( copper and nickel) .
Metals are commonly found in the earths crust as ores. Ores are metal compounds in which the metal atoms are chemically combined with other atoms. The purification process used to isolate metals is called smelting, although some metals are isolated through elctrolysis (e.g. copper) , or mined in their pure state ( e.g. silver and gold)
172
what is electrolysis
Electrolysis is a process that uses electricity to break down a compound into its elements. It works by passing an electric current through a liquid (called an electrolyte) that contains ions.
For example:
Splitting water into hydrogen and oxygen using electricity.
2𝐻2𝑂→2𝐻2+O2
In simple terms, electrolysis uses electricity to split a substance into its basic parts.
173
what is a compound
A compound is a substance made when two or more different elements are chemically bonded together. The elements in a compound are combined in a fixed ratio and cannot be separated by physical methods.
For example:
Water (H₂O) is a compound made of hydrogen and oxygen.
Salt (NaCl) is a compound made of sodium and chlorine.
In simple terms, a compound is like a team of different atoms working together as one substance.
174
metals are commonly found in the earths crust as ...
ores
175
the purification process used to isolate metals is called
smelting although some metals are isolated through electrolysis or mined in their pure state
Electrolysis is a process that uses electricity to break down a compound into its elements.
176
combined molten metals create what
alloys
177
Chemical Properties (Reactions) of Metals.
Chemical properties are those that describe how a material reacts with its surroundings.
Typically, when discussing the chemical properties of metals, the reactions with oxygen, water and acids are of greatest importance.
The reactivity of metals with these 3 substances can vary significantly from interly inert (gold and water) to explosive (sodium and water) .
Many metals will react with oxygen from the air to form a coating of metal oxide on the surface. this corrosion can be prevented, or at least slowed, by applying a layer to the metal to prevent oxygen from reaching the metal surface.
NOTE: in the case of iron, this corrosion is called rusting
Comparing metal reactions (1/3)
Metal:
Action in H2O:
*sodium calcium: strong bubbling in cold water
\
*magnesium: gas given off in hot water
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*aluminium, zinc: bubbling in steam
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*iron, lead: slow bubbling in hot water
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*copper, silver, gold: no reaction
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Comparing metal reactions cont (2/3)
Metal:
Reaction with acid:
*sodium, calcium: violent bubbling in cold acid
\
*magnesium: strong bubbling in cold acid
\
*zinc: strong bubbling in cold acid
\
*iron,lead: slow bubbling in warm acid
\
*copper, silver, gold: no reaction in warm acid
Comparing metal reactions cont (3/3)
Metal:
Reaction with oxygen:
*Sodium, Calcium: ignites in cold air to give a solid
\
*magnesium: flares when heated to give a solid
\
*aluminium,zinc,iron: burn when heated to give a solid
\
*lead, copper: do not burn/ react slowly to give a solid
\
*silver, gold: no reaction with oxygen
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Physical properties on Non-metals
* Non metals are not ductile , i.e. they cannot be made into thin wires.
* Non metals are insulators or poor conductors of electricity and heat
* at room temperature, they can be solids liquids or gases.
Chemical properties (Reactions) of non metals
* They react with oxygen to form acidic oxides or neutral oxides
* they do not react with water (steam)
* they do not react with acids
* they react with chlorine to form covalent chlorides
(Covalent means sharing electrons. It's when atoms stick together by sharing their outer electrons to form a bond.)
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what physical property do non metals not have
they are not ductile or malleable
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non metals are poor conductors of electricity and heat. this makes them what
isulators
182
when non metals react with oxygen they form what
acidic oxides or neutral oxides
183
non metals react with chlorine to form what
covalent chlorides
184
non metals do not react with what
water (steam) and acids
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a halogen will react with a halide ion, in solution, from any halogen below it on the periodic table.
the more active halogen will gain electron(s) while the anion of the other halogen will lose electron(s) .
if chlorine gas is bubbled through a solution of sodium bromide, then the solution will turn from colourless gas to an orange colour. This is because chlorine is more reactive than bromine. so a chlorine atom will take the electron from a bromide ion and become chloride while the bromide becomes bromine.
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Metals Vs Non-metals
Metals:
*Lutre: Yes
*Hardness: Very hard (Except group 1 and some of group 2)
*ductile / highly malleable (except zinc)
*good conductors of heat and electricity
*melting & boiling points: high
*state (at room temperature): solid (except mercury and gallium)
*Density: high (except group 1)
Metals Vs Non-metals
Non-metals:
*Lustre: No
*Hardness: not hard (Except diamond - hardest known substance)
*non-malleable / non ductile brittle
*poor conductors of heat and electricity (except carbon - graphite)
*melting & boiling points: low (except diamond)
*state (at room temperature): solid, liquid, gas
*Density: low (except diamond)
187
non metals density are low except what element
diamond
188
metals density is high except what elements
group 1 elements
189
metals states at room temperature are solids except what elements
mercury and gallium
190
non metals' boiling points are low except which element
diamond
191
non metals are poor conductors of heat and electricity except which element
except carbon a form of graphite
192
all metals are ductile and highly malleable except which element
Zinc
193
all metals are very hard except..
group 1 and some of group 2
194
all non metals are not hard except..
diamond - hardest known substance
195
the melting & boiling points of metals are
high
196
the melting & boiling points of non metals are
low (except diamond)
197
the order of reactivity of some elements is shown below.
most reactive
sodium
calcium
magnesium
aluminium
carbon
zinc
iron
lead
hydrogen
copper
silver
gold
least reactive
predict, giving reason for your answer, whether the following pairs of substances react, and provide any expected observations(s).
(a) iron and copper sulfate solution
(b) magnesium dilute hydrochloric acid
(c) aluminium oxide and carbon
(a) Iron and Copper Sulfate Solution
Prediction: A reaction will occur.
Reason: Iron is higher than copper in the reactivity series, so it can displace copper from its sulfate solution.
Observation: The blue color of the copper sulfate solution will fade, and reddish-brown copper will form on the iron surface.
(b) Magnesium and Dilute Hydrochloric Acid
Prediction: A reaction will occur.
Reason: Magnesium is higher than hydrogen in the reactivity series, so it will react with the acid, producing hydrogen gas.
Observation: Effervescence (bubbles of hydrogen gas) will form, and the magnesium will dissolve.
(c) Aluminium Oxide and Carbon
Prediction: No reaction will occur.
Reason: Carbon is lower than aluminum in the reactivity series, so it cannot reduce aluminum from its oxide.
Observation: There will be no visible change.
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why is silicon difficult to classify as metal or non metal
Silicon is hard to classify because it has properties of both metals and non-metals. It conducts electricity like a metal but is brittle and forms covalent bonds like a non-metal. This makes it a metalloid.
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