Chemistry C 2 Flashcards
1
Q
What is an element?
A
An element consists of the same kind of atoms.
Examples: Cl, C, H, He
2
Q
What is a compound?
A
A compound consists of two or more elements chemically combined.
Example: H2O
3
Q
What is a mixture?
A
A mixture consists of two or more substances which are not chemically combined.
4
Q
What is a property of group 1 alkali metals?
A
Highly reactive with water.
5
Q
How does reactivity change down group 1?
A
Reactivity increases down the group.
6
Q
What are the melting and boiling points of group 1 alkali metals?
A
Relatively low melting and boiling points.
Melting and boiling points decrease down the group.
7
Q
What is the nature of metallic bonding in group 1 alkali metals?
A
Weak metallic bonding.
8
Q
How does the density of group 1 alkali metals compare to other metals?
A
Less dense than other metals.
9
Q
How does density change down group 1?
A
Density increases down the group.
10
Q
How can we predict the properties of unknown group 1 metals?
A
If the atomic number is higher than known elements, it will have higher density, increased reactivity, and a lower melting point.
11
Q
What does Metallic Character refer to?
A
Metallic Character refers to its ability to lose electrons and form positive ions.
12
Q
How does metallic character change across a period?
A
As you move from left to right, the metallic character of the element decreases and they become more non-metallic.
13
Q
What happens to the number of protons in the nucleus as you move across a period?
A
As the number of protons in the nucleus increases, so does the positive charge of the nucleus.
14
Q
What is the trend in reactivity for Group 2 elements?
A
Group 2 elements (Alkaline earth metals: Be, Mg, Ca, Sr, Ba, Ra) are less reactive, and reactivity increases down the group.
15
Q
What are the characteristics of Transition metals?
A
Transition metals (Groups 3-12) are dense with high melting and boiling points.
16
Q
What are the properties of Noble gases?
A
Group 18 elements (Noble gases: He, Ne, Ar, Kr, Xe, Rn) are inert and unreactive.
17
Q
What is Metallic Bonding?
A
Metallic Bonding is the attraction between positive metal ions and the sea of delocalised electrons.
18
Q
Where is Metallic Bonding found?
A
Metallic Bonding is present in metals and their alloys.
19
Q
What is the structure of metals and their alloys?
A
Metals and their alloys have a lattice structure with a regular arrangement of positive metal ions.
20
Q
What allows electrons to conduct electricity in metals?
A
The outer shell electrons of the metal atoms are delocalised and free to move.
21
Q
What is the malleability of metals due to?
A
The malleability of metals is due to the lattice structure, allowing atoms to move around each other without breaking the metallic bond.
22
Q
What is the structure of graphite?
A
Graphite has a giant covalent structure where each carbon atom forms three covalent bonds with other carbon atoms, creating layers of hexagonal rings.
There are no covalent bonds between the layers.
23
Q
What is unique about the electrons in graphite?
A
Graphite has delocalised electrons, which are free to move between the layers, allowing it to conduct electricity.
Delocalised = Free electrons.
24
Q
What are the practical uses of graphite?
A
Graphite is useful for electrodes in batteries, electrolysis, and as a lubricant due to its slippery layers.
The forces between the layers in graphite are slippery.
25
What are the properties of diamond?
Diamonds are very hard, have a high melting point, are non-conductive, and are used in cutting tools, jewelry, and industrial applications.
26
What are the properties of graphite?
Graphite is a good lubricant, conducts electricity, and is soft and slippery.
27
What is a common use of graphite in everyday items?
Graphite is used in pencils.
28
What is the melting point of diamond?
Diamond has a very high melting point of almost 4000°C.
29
What type of bonds are present in diamond?
Diamond has very strong carbon-carbon covalent bonds.
30
What is the hardness of diamond?
Diamond is very hard due to the strong covalent bonds.
31
Does diamond conduct electricity?
Diamond does not conduct electricity because all the electrons are tightly held between the atoms and aren't free to move.
32
What is the melting point of diamond?
Diamond has a very high melting point of almost 4000°C.
33
What type of bonds are present in diamond?
Diamond has very strong carbon-carbon covalent bonds.
34
What is the hardness of diamond?
Diamond is very hard due to the strong covalent bonds.
35
Does diamond conduct electricity?
Diamond does not conduct electricity because all the electrons are tightly held between the atoms and aren't free to move.
36
What property makes diamond very hard?
The structure of diamond makes it very hard.
37
What are some uses of diamond due to its hardness?
Diamond is useful for cutting tools, such as diamond-tipped glass cutters and oil rig drills.
38
What are giant covalent structures?
Giant covalent structures are large networks of atoms bonded together by covalent bonds.
39
What is the giant covalent structure of diamond?
In diamond, each carbon atom forms four single covalent bonds with other carbon atoms.
40
What is the electron arrangement of carbon?
Carbon has an electron arrangement of 2,4.
41
Is diamond considered a molecule?
No, diamond is not a molecule because the number of atoms in a diamond can vary depending on the size of the crystal.
42
What are ionic compounds?
Ionic compounds are crystalline solids made of ions.
43
What are the melting and boiling points of ionic compounds?
Ionic compounds have high melting and boiling points.
44
Do ionic compounds conduct electricity?
Ionic compounds conduct electricity when melted.
45
Are ionic compounds soluble in water?
Many ionic compounds are soluble in water but not in nonpolar liquids.
46
What are covalent compounds?
Covalent compounds are gases, liquids, or solids made of molecules.
47
What are the melting and boiling points of covalent compounds?
Covalent compounds have low melting and boiling points.
48
Do covalent compounds conduct electricity?
Covalent compounds are poor electrical conductors in all phases.
49
Are covalent compounds soluble in nonpolar liquids?
Many covalent compounds are soluble in nonpolar liquids but not in water.
50
What is a nonpolar substance?
A nonpolar substance is any substance that won't mix with water.
## Footnote
Example: Oil.
51
What is a polar liquid?
A polar liquid is a liquid that can mix with water.
## Footnote
Example: Water.
52
What are covalent bonds?
Covalent bonds occur when atoms share electrons to gain a full outer shell and become stable.
53
Which atoms commonly form covalent bonds?
Atoms such as Hydrogen and Oxygen form covalent bonds to create diatomic molecules.
54
What do covalent bonds in compounds represent?
Each covalent bond represents a single electron being shared.
55
What types of bonds can exist in covalent compounds?
In covalent compounds, there can be single, double, or triple bonds.
56
What are the properties of covalent bonds?
Covalent bonds have low melting and boiling points.
57
How strong are covalent bonds?
Covalent bonds are strong, but the bonds between covalent molecules are not.
58
Why do covalent compounds have low melting and boiling points?
This is due to the weak bonds between covalent molecules.
59
What is the electrical conductivity of covalent molecules?
Covalent molecules have poor electrical conductivity.
60
Why do covalent molecules have poor electrical conductivity?
Covalent molecules share electrons and are neutral, meaning there are no free electrons to carry a charge.
61
What are the properties of ionic compounds?
1. High melting and boiling points.
## Footnote
This is due to the large amount of energy required to treat the strong electrostatic bonds between positively and negatively charged ions.
62
How do ionic compounds conduct electricity?
They conduct electricity well when molten but not in solid form.
## Footnote
In a solid, the ions are fixed in position and unable to move. When molten, they can move freely and carry a charge.
63
Are ionic compounds soluble in water?
Many are soluble in water but not in nonpolar liquids.
## Footnote
Water is a polar molecule, which means it has a positive end and a negative end. It has strong forces of attraction between charged ions and forms hydrogen bonds, breaking the crystalline ionic bonds.
64
What is a dot and cross diagram?
A dot and cross diagram models the transfer of electrons from metal atoms to non-metal atoms.
## Footnote
Electrons from one atom are shown as dots, and electrons from the other atom are shown as crosses. For example, when sodium reacts with chlorine, electrons transfer from sodium atoms to chlorine atoms.
65
What is an ion?
An ion is an atom that has lost electrons to gain a full outer shell and becomes stable.
66
What happens to a sodium atom when it loses an electron?
A sodium atom (atomic number 11, electron arrangement 2, 8, 1) loses its outer electron, resulting in 11 protons and a +1 charge.
67
What does chlorine do in terms of electrons?
Chlorine will gain an electron, giving it a -1 charge.
68
How do ions gain a charge?
Ions will gain a charge depending on how many electrons they lose or gain.
69
What is ionic bonding?
An ionic bond is a type of chemical bond formed through an electrostatic attraction between two oppositely charged ions.
70
What is a cation?
A cation is usually a metal that has lost electrons.
71
What is the structure of ionic compounds?
Ionic compounds have a regular arrangement of alternating positive and negative ions, e.g., sodium chloride.
72
What are the properties of ionic bonds?
Ionic bonds have high melting and boiling points.
73
What are isotopes?
Atoms with the same atomic number, but different mass numbers are called isotopes.
74
Are most isotopes stable?
Yes, most isotopes are stable in the terrestrial sense and not radioactive.
75
What are the three types of hydrogen isotopes?
The three types of hydrogen are:
1. Hydrogen-1 (most common)
2. Hydrogen-2 (deuterium)
3. Hydrogen-3 (tritium)
## Footnote
Hydrogen-2 is sometimes called deuterium.
76
What do isotopes of the same element have in common?
Isotopes of the same element have the same chemical properties because they have the same number of electrons.
77
What is the electronic configuration of isotopes?
Isotopes have the same electronic configuration because they have the same number of electrons.
78
How is Helium-4 formed?
Helium-4 is formed in the sun through nuclear fusion.
79
Can Helium-4 be formed by the decay of another isotope?
Yes, Helium-4 can also be formed by the decay of Tritium.
80
What are orbitals?
Electrons orbit the nucleus of an atom in shells known as orbitals.
81
How many electrons can the first orbital contain?
The first orbital can only contain 2 electrons.
82
How many electrons can the second orbital contain?
The second orbital can contain up to 8 electrons.
83
What is the electron configuration of Calcium?
Calcium, which has an atomic number of 20, has an electron configuration of 2,8,8,2.
84
What should the sum of the electrons equal?
The number of electrons should add up to the atomic number, which is 20 for Calcium.
85
What does the valence number refer to?
The valence number refers to the number of electrons in an atom's outer shell.
86
What is the atomic number of Sodium?
Sodium has an atomic number of 11.
87
What is the electron arrangement of Sodium?
Sodium has an electron arrangement of 2,8,1.
88
What is the valence of Sodium?
Sodium has a valence of 1.
89
Where is Sodium located in the periodic table?
Sodium is located in group 1 of the periodic table.
90
How is the periodic table organized?
The periodic table is ordered into groups and periods.
91
What do the vertical columns in the periodic table represent?
The vertical columns are Groups and coincide with the number of outer shell electrons.
92
What do the horizontal columns in the periodic table represent?
The horizontal columns are periods, and as the number of energy levels increase, we go down a period.
93
Why do outer shell electrons have higher energy?
Electrons in outer shells have higher average energy and travel farther from the nucleus than those in inner shells.
94
What makes elements with 1 or 7 outer shell electrons highly reactive?
Elements with 1 or 7 electrons in their outer shell are the most reactive because it is relatively easy to gain or lose a single electron.
95
Give examples of highly reactive elements.
Examples include Potassium and Chlorine.
96
What about elements with 2 or 6 outer shell electrons?
The next most reactive are elements with 2 or 6 electrons in their outer shell, such as Calcium or Oxygen.
97
How does reactivity change with energy levels?
As we add energy levels and move into different periods, the reactivity tends to increase.
98
Which is more reactive, Potassium or Lithium?
Potassium is more reactive than Lithium.
99
What is the characteristic of atoms with a full valence shell?
Atoms with a full valence shell are unreactive, such as the noble gases like Neon and Helium.
100
Is the number of protons in an atom the same as the number of electrons?
Yes
101
What does the atom number represent
The number of protons in an atom
102
What is atomic mass?
Atomic mass is the number of protons and neutrons added together
103
What charge do protons have and how much mass do they have?
+1 charge and mass of 1
104
What charge do electrons have and how much mass do they have?
-1 charge and mass of 0.0005
105
What charge do neutrons have and how much mass do they have?
They are neutrally charged and a mass of 1
106
What is the trend in density for group VII halogens?
There is a trend towards increasing density down the group VII halogens from chlorine to bromine to iodine. This trend can be attributed to the increase in molecular size and mass of the halogen molecules as you move down the group.
107
How does reactivity change among group VII halogens?
There is a trend of decreasing reactivity from chlorine to iodine. This trend can be explained by the increasing size of the halogen atoms, electronegativity, and increasing atomic pressure.
108
What are the appearances of chlorine, bromine, and iodine at room temperature and pressure?
Chlorine is a pale yellow-green gas. Bromine is a red-brown liquid. Iodine is a grey-black solid.
109
What are displacement reactions in the context of halogens?
Displacement reactions involve halogens and halide ions.
110
111
What are hallide ions?
Hallide ions are the ions of halogens that occur when a more reactive halogen displaces a less reactive halogen from its hallide ion in a solution.
112
What principle do displaced reactions follow?
Displaced reactions follow the general principle where a more reactive element displaces a less reactive element from its compound.
113
Provide an example of a displaced reaction.
An example is the reaction between chlorine and potassium iodide solution: Cl2 + 2KI → 2KCl + I2.
114
What is electronegativity?
Electronegativity refers to an atom's ability to attract electrons to itself.
115
What happens to electrons as electronegativity increases?
As electronegativity increases in an atom, electrons will be more attached to it.
116
What are transition elements?
Transition elements are found in group 3-12 of the periodic table.
117
What are some properties of transition elements?
They exhibit a wide range of physical and chemical properties, including high melting and boiling points, and high densities.
118
In what industries are transition elements commonly used?
They are commonly used in various industrial applications, including alloys, electronics, catalysts, and jewelry.
119
What are the properties of noble gases?
Noble gases are highly unreactive.
120
What are the properties of metals?
Metals are generally highly thermally conductive, malleable, and ductile. They have varying electrical conductivity depending on the type of metal.
121
What are the properties of non-metals?
Non-metals generally have poor thermal conductivity and poor electrical conductivity, with exceptions like graphite. They are usually brittle, not malleable, and not ductile.
122
How do the melting and boiling points of non-metals compare to metals?
Non-metals generally have lower melting and boiling points compared to metals.
123
What is the general equation for the reaction with steam?
Metal + steam → metal oxide + Hydrogen
124
What is the reaction of Sodium with water?
Sodium + water → Sodium oxide + Hydrogen gas
## Footnote
Example: 2Na + 2H2O → NaOH + H2
125
What do metals generally react with to form salt and hydrogen gas?
Metals generally react with dilute acids.
## Footnote
Example: Zinc + Hydrochloric acid → Zinc chloride + hydrogen gas (2Zn + 2HCl → ZnCl2 + H2).
126
Which metals react readily with dilute acids?
More reactive metals such as magnesium and zinc react readily with dilute acids like hydrochloric acid or sulfuric acid.
127
What is the general equation for the reaction of metals with acids?
Metal + Acid → Salt + Hydrogen gas.
128
Do most metals react with cold water?
Most metals do not react with cold water.
129
Which metals react vigorously with water?
More reactive metals such as sodium and potassium react vigorously with water.
130
What do reactive metals form when they react with steam?
Reactive metals form metal oxide and hydrogen gas when they react with steam.
131
What is aluminium used for in aircraft manufacture?
Aluminium is used in the production of aircraft because of its low density, which helps reduce the overall weight without losing structural integrity.
132
Why is aluminium preferred for overhead electrical cables?
Aluminium is preferred for overhead electrical cables due to its combination of low density and good electrical conductivity.
133
What is the use of aluminium in food containers?
Aluminium is used in food containers because it is resistant to corrosion.
134
What is copper widely used for?
Copper is widely used in electrical wiring.
135
Why is copper used in electrical wiring?
Copper is used due to its excellent electrical conductivity.
136
What are alloys?
Alloys are materials formed by mixing a metal with one or more other elements.
137
What is brass?
Brass is a mixture of Copper (Cu) and Zinc (Zn).
138
What is stainless steel?
Stainless steel is primarily iron (Fe) with chromium (Cr), nickel (Ni), and sometimes carbon (C).
139
Why are alloys useful?
Alloys can be harder and stronger than pure metals, making them more useful.
140
What is a common use of stainless steel?
Stainless steel is used in cutlery due to its hardness, strength, and resistance to rusting.
141
How do different sized atoms in alloys affect their structure?
In alloys, the different sized atoms disrupt the regular arrangement of metal atoms, preventing layers from sliding over each other.
142
What is the effect of structural disruption in alloys?
Structural disruption makes alloys harder and stronger than pure metals, enhancing their utility.
