Chemistry Flashcards
All of the topics and things to know for the exam
What is an Atom?
the smallest particle of a chemical element that can exist.
What are the two parts that at atom is made up of?
The positively charged nucleus in the middle and the electron shells that surround the nucleus
What is the nucleus and what is inside?
The nucleus is in the middle of the atom and it consists of protons and neutrons
What are the three subatomic particles?
Protons, Neutrons and Electrons.
What is a proton?
is a positively charged subatomic particle found in the nucleus. It has a relative charge of +1 a mass of 1 and it determines what element the atom is
What is a neutron?
a neutrally charged subatomic particle found inside the nucleus. It has a relative charge of 0 a relative mass of 1 and it helps stabilise the nucleus. The numbers of neutrons can vary between atoms of the same element. e.g. calcium always has 20 protons, but it could have 18 neutrons and another could have 20.
What is an electron?
a negatively charged subatomic particle that is found in the electron shells orbiting around the nucleus. It has a relative charge of -1 a mass of approximately 0 and it balances out the positive charge of the nucleus. e.g. Calcium has 20 protons so it has 20 electrons.
How can we sort the elements?
By atomic number and atomic mass/mass number
What is the atomic number?
the number of protons ( and electrons) in an atom
What is the atomic mass/ mass number?
Number of protons + number of neutrons
What is nuclear symbol notation?
atomic mass over atomic number next to element symbol - larger number goes on top
How do you determine the number of protons or electrons in an element?
The atomic number tells you the amount of protons and electrons.
How do you determine the number of neutrons in an element?
The atomic mass minus the atomic number gives you the amount of neutrons.
How do electrons arrange themselves?
They arrange themselves in shells, filling up from the innermost shell first.
What is the electron configuration for the no. of electrons per shell.
First number is shell second number is max amount of electrons in that shell 1 - 2, 2 - 8, 3 - 8, 4 - 2
What are valence electrons?
Valence electrons are the electrons in the outermost shell of an atom.
Determine the number of protons, neutrons and electrons in: 16 O
8
P = 8, E = 8 N = 16-8 = 8
How are atoms arranged on the periodic table?
They arranged by the increasing order of atomic number. The atomic mass mostly increases too.
What is the pattern for the electron configuration for the first 20 elements?
As we go across a row, we are adding more electrons to the same electron shell until it is full (then we go to the next row). Last number increases by 1 and so does electron shells as you go down the columns.
What are the rows called on the periodic table and what do they tell us?
periods and they denote what electron shell is the valence electron shell
What are the columns on the periodic table called and what do they elements in them have in common?
groups and elements in the same group have similar chemical properties (how they react)
What are the group names?
Group 1. - Alkali metals, Group 2. Alkaline metals, Group 3-12. - Transition metals, Group 17. - Halogens, Group 18. - Noble gases
What are the two rows at the bottom of the periodic table called?
Row 8: Lanthanide series (Lanthanoids), Row 9: Actinide series (Actinoids)
What is ionic bonding?
When atoms gain or lose electron. This causes them to be more stable/have a full outer shell. Happens between metals and non-metals
What happens when an atom gains electrons?
It becomes a negatively charged ion (anion) and the name of the element changes slightly (suffix - ide)
What happens when an atom loses electrons?
It becomes a positively charged ion (cation)
Name the ion charge for each group on the periodic table?
Group 1 = +1, Group 2 = +2, Group 3 - 12 = varies, Group 13 = +3, Group 14 = + or - 4, Group 15 = -3, Group 16 = -2, Group 17 = -1 ,Group 18 = 0
How many protons, neutrons and electrons does this have: 86 37 RB⁺
P = 37 E = 36 (because it has a positive charge so it has lost and electron) N = 86-37 = 49
Define valency?
the magnitude (size) of the ion charge
Name the valency for each group of the periodic table.
Group 1 = 1, Group 2 = 2, Group 3 - 12 = varies, Group 13 = 3, Group 14 = 4, Group 15 = 3, Group 16 = 2, Group 17 = 1, Group 18 = 0
How do you denote the charge and valency of transition metals?
Transition metals can have multiple ion forms so we denote them using roman numerals. note: they will always be positive
Determine how many protons, electrons, and neutrons are in this element. Copper (II)
P = 29 E = 27 (because it has an positive ion charge of 2+) N = 63 - 29 = 34
What are the three elements that go against the rule of ion charges and what is the only form they have?
Zinc - Zn²+, Silver - Ag+, Lead - Pb²+
Identify the ion charge of the following using your periodic table: Strontium, Sulfide, Titanium (II) ,Arsenide, Cobalt (V)
Strontium - 2+, Sulfide = -2, Titanium (II) = 2+, Arsenide = -3, Cobalt (V) = 5+
How do atoms lose or gain electrons?
By getting them from another atom that also needs to fill its outer shell. For example, Lithium has 3 electrons, therefore 1 in its outer shell and Fluorine has 9 electrons, therefore 7 in its outershell, so these two can pass electrons onto each other so they can both have a full outershell.
What happens when a cation and an anion attract?
They form ionic compounds.
Can two positives combine to share electrons?
No only a positive and a negative can combine.
Write the chemical equation for when Lithium and Fluorine combine.
Li+ plus F+ = LiF = Lithium fluoride.
Can two or more atoms combine to achieve full outer shells?
Yes
Write the chemical equation for when two lithium’s and one oxygen combine.
Li⁺ + Li⁺ plus O²- = Li₂O = lithium oxide
What is a method you can use to easily write the formulas of ionic compounds?
The swap and drop. In this method you swap the numbers at the top of the element name and drop them below. For example, Li¹⁺ and O²- will swap to become Li₂O.
How do you name ionic compounds?
Name the metal ion (positive cation) and then name non-metal ion ( negative anion) and end element with suffix “ide”
Name the following: K₃P, MgCl₂, AlN
- Pottasium phosphide, 2. Magnesium chloride, 3. Aluminium Nitride
What do you do when writing the formulas of Ionic compounds?
Use the swap and drop method but make sure to work out their ion charge first. Write the CATION (metal) first and then the ANION (non-metal)
Write the formula for the following : Magnesium Nitride, Manganes (IV) sulfide, Magnesium oxide, Iron (II) bromide.
- Mg₃N₂ 2. Mn₂S₄ 3. MgO 4. FeBr₂
So far we have looked at monoatomic (one atom) ions. What is the other type?
Polyatomic. There are 8 types we know.
What is a polyatomic ion?
An ion composed of two or more atoms.
What is the formula for Carbonate
CO₃ ²⁻
What is the formula for Bicarbonate/hydrogen carbonate
HCO₃⁻
What is the formula for Sulfate?
SO₄²-
What is the formula for Phosphate?
PO₄³⁻
What is the formula for Hydroxide?
OH⁻
What is the formula for Ethanoate
CH₃COO⁻
What is the formula for Ammonium
NH₄⁺
What is the formula for the nitrate
NO₃⁻
What happens when writing formulas for polyatomic ions in compounds?
The ion has to stay together, therefore if the number being swapped and dropped is larger than one than the ion needs brackets around it. For example, Mg²⁺ and OH⁻ ((OH⁻) being the polyatomic ion) combining needs to be Mg(OH)₂
What is a covalent compound?
involves the sharing of electrons between non-metals to get a full outer shell
What do you need to do when naming covalent compounds?
preix atom1 prefix atom2-ide. We need to specify how many of each atom there is which is why we use the prefixes. If the first atom has only one atom then you don’t say mono for it.
Name the prefixes.
mono, di, tri, tetra, penta, hexa, hepta, octa, nona, deca
Name the covalent compounds with special common names.
H₂O - Water, NH₃ - Ammonia, CH₄ - Methane, C₆H₁₂O₆ - Glucose, O₂ - oxygen gas, Cl₂ - chlorine gas, N₂ - nitrogen gas, H₂ - hydrogen gas
What are the substances that go into a chemical reaction called?
Reactants
What are the substances that are formed in a chemical reaction called?
Products
Write the following reactions as word equations: Hydrochloric acid reacts with magnesium metal. As the metal dissolves, hydrogen gas bubbles off and magnesium chloride is formed.
Hydrochloric acid + Magnesium metal —-> hydrogen + magnesium chloride
What does the subscript in a chemical compound apply to?
Only the element on the left
What does a large coefficient in front of the compound apply to?
The whole compound
What does a subscript outside a bracket do?
It multiplies the whole bracket
State the number of each type of atom in the following: 1. MgSO₄, 2. 4Co(CH₃COOH)₃, 3. 3Al₂(Cr₂O₇)₃
- One magnesium, one sulfur, four oxygen 2. 4 cobalt, 24 carbon, 24 oxygen, 48 hydrogen 3. 6 aluminium, 18 Chromium, 63 oxygen
What does the law of conservation of mass state?
that the number and type of atoms that we start with will be the same after the reaction. The only thing that changes is how they are arranged. This is known as balancing equations
Can you change the chemicals that you start and finish with in an equation?
No we can only change the amount of chemicals with large coefficients
How do you balance equations?
- Find the elements you are working with 2. Find the amount of atoms of each element on the left hand side and the right hand side 3. Make the amount of atoms of each element the same on both sides by adding large coefficients.
Balance these equations.: 1. NaCl +CuO —-> Na₂O + CuCl₂ 2. HCl + Ca(OH)₂ —> CaCl₂ +H₂O
- 2NaCl +CuO —-> CuCl₂ 2. 2HCl +Ca(OH)₂ —>CaCl +2H₂O
What is a Gas test?
Test to identify the type of gas being produced in chemical reactions
What are the gas tests?
The pop test for Hydrogen, The glowing splint test for Oxygen and the limewater test for Carbon dioxide.
What happens in the pop test?
A flame is introduced to hydrogen gas and a pop or squeak noise is heard
What happens in the glowing splint test?
A glowing splint is introduced to oxygen gas and the splint will reignite
What happens in the limewater test?
Carbon dioxide is bubbled through lime water. The lime water goes cloudy.
What are the four different states that matter can exist in?
Solid, Gas, Liquid and Aqueous
How do we denote these states?
solid - (s), liquid - (l), gas - (g), aqueous - (aq)
What is a sign that something is a solid
metal by itself, precipitate, insoluble salt
What is a sign that something is a liquid
water
What is a sign that something is a gas
known gases (O₂, H₂, CO₂)
What is a sign that something is a aqueous
substance dissolved in water, solution, acids, soluble salt
Write the balanced equation with the states of matter for this: Hydrochloric acid reacts with solid calcium carbonate to form a solution of calcium chloride and water. Carbon dioxide gas also forms
2HCl(aq) + CaCO₃(s) —–> CaCl₂(aq) + H₂O (l) + CO₂(g)
Define an isotope
Atoms with the same number of protons and different numbers of neutrons. There is isotopes for every atom.
Given an example of an isotope
Hydrogen - 1, Hydrogen - 2 and Hydrogen - 3. Hydrogen 1 has 0 neutrons, 2 has 1 neutron and 3 has 2 neutrons.
Explain the masses on the periodic table in relation to isotopes.
On the periodic table, due to all the atomic numbers being decimals, shows the little extra bits of mass that are the isotopes. The mass takes into account the different isotopes and their natural abundance.
When is the nucleus unstable?
A nucleus is stable it can exist indefinitely. However, it the number of neutrons is too much or too little it becomes unstable.
What are unstable isotopes?
Unstable isotopes are radioactive
Give an example of an unstable isotope?
Hydrogen -3
What is radioactive decay?
the process of the unstable nucleus trying to become more stable.
What happens during the radioactive decay process?
It releases ionising radiation, causing other surrounding atoms to become ions (lose or gain electrons)
What are the types radiation that radioactive decay can release?
alpha (α), beta (β) and gamma (ɣ)
what does an alpha particle consist of?
an alpha particle consists of 2 protons and 2 neutrons
How is an alpha particle written?
4 α OR 4 He
2 2
Write an equation for the alpha decay of:
289 Np
93
289 Np —-> 4 α + 285 Pa
93 2 91
What are three facts about alpha particles?
- slow moving because it is “heavy”
- very strong ionising ability
- low penetrating ability - stopped by paper, air and sking
What are beta particles
they are high energy electrons that are emitted as the nucleus changes
What do Beta particles consist of?
Beta particles are also electrons so they have a mass of 0 and a charge of -1
What happens in radioactive decay when a Beta particle is emitted.
A neutron changes into a proton and a beta particle is emitted. This is to make the nucleus more stable. It is essentially an electron being added into the nucleus.
How can you write a beta particle?
0 β OR 0 e
-1 -1
What do we see when a beta particle is emitted?
The new atom has one more proton and one less neutron (the mass stays the same)
Write the equation for the beta decay of:
234 Th
90
234 Th —> 0 β + 234 Pa
90 -1 91
What are three facts about the beta particle?
- medium ionising power
- moderate penetrating ability (stopped by aluminium)
- moderate particle speed (0.3 -0.8 times the speed of light)
How do gamma particles get emitted?
For them to be emitted a beta or alpha particle must be emitted first
Why does it have to happen after a beta or alpha particle?
Because when the alpha and beta particles are emitted the daughter nuclide (the one formed) can have too much energy and so it release energy in the form of gamma radiation
How do we write the gamma particle?
0 ɣ
0
How do you write an equation for gamma decay?
Write alpha or beta decay equation and on the daughter nuclide (atom formed) write an asterisk. Then on a new line write the daughter nuclide with the asterisk the arrow then the gamma particle plus the daughter nuclide without the asterisk.
Write the equation for gamma decay for:
934 Th —> 0 β + 234 Pa*
90 -1 91
234 Pa* —> 0 ɣ + 234 Pa
91 0 91
What are three facts about the gamma particle?
- low ionising ability
- very high energy and high penetrating level (stopped by led)
- moves at the speed of light
Can radioactive decay be controlled?
No, it is a spontaneous and random process and it isn’t affected by factors such as temperature.
What does each radioactive isotope have?
A half life
What is a half life?
how long it takes for half the sample to decay
