Edexcel C2 Revision Cards

Front 1

1. Where are metals found on the periodic table?
2. How did Mendeleev arrange elements on his periodic table?
3. What was special about the way he did this?

Back 1

1. On the left of the metal staircase.
2. Elements with similar properties in vertical columns; arranged in order of increasing mass.
3. He left gaps where he thought there must be an element that hadn't been discovered yet. He used the periodic table to predict the properties and mass of the missing elements.

Front 2

1. Describe the structure of an atom.
2. Describe the relative charge of each subatomic particle.
3. Describe the relative mass of each subatomic particle.
4. Explain why atoms are neutral.

Back 2

1. Protons and neutrons are located in the nucleus in the centre of the atom and electrons are arranged on shells around the outside.
2. Protons are positive; neutrons are neutral; and electrons are negative.
3. Protons and neutrons have a relative mass of 1 and electrons are so tiny that their relative mass is virtually 0.
4. Atoms are neutral because they have the same number of protons and electrons so the positive and negative charges cancel out.

Front 3

1. What does the atomic number tell you?
2. What does the mass number tell you?
3. What is relative atomic mass?
4. What are groups and periods?

Back 3

1. The number of protons in the nucleus (this is always equal to the number of electrons).
2. The mass of the nucleus (protons + neutrons).
3. The mass of the atom compared to a carbon atom.
4. Groups are columns, all elements in a column have the same number of electrons in their outer shell and similar properties. Periods are rows, all elements in a period have the same number of electron shells.

Front 4

HIGHER ONLY
1. What is an isotope?
2. How can you calculate the relative atomic mass of an element that has different isotopes?

Back 4

1. An element that exists in different forms that have the same number of protons but different numbers of neutrons in their nuclei.
2. Multiply the percentage of one isotope by its RAM and do the same for the other isotope. Add these together and divide by 100.
E.g. Chlorine has 2 isotopes: 25% have a RAM of 37 and 75% have a RAM of 35. 25 x 37 = 925. 75 x 35 = 2625. 925 + 2625 =3550. 3550/100 = 35.5.

Front 5

1. What does electron configuration mean?
2. How do electron shells fill?

Back 5

1. The arrangement of electrons in shells around the nucleus of the atom.
2. First shell = 2 max; second and third shells = 8 max.

Front 6

1. What is an ion?
2. How do ionic compounds form?
3. How does the group number tell you what charge an atom will be if it becomes an ion?

Back 6

1. An atom that has gained or lost electrons and so become charged.
2. A metal atom loses electrons to become a cation; these electrons are passed to non-metal atoms so that they become negatively charged anions. They are held together by electrostatic forces between the opposite charges.
3. Groups 1-3 will have the same charge as their group number (+); groups 5-7 will have a charge of 8 - their group number (-)

Front 7

1. How do you work out the formulae of ionic compounds?
2. What is a compound ion?
HIGHER ONLY
3. Describe the structure of an ionic compound

Back 7

1. Work out the charges on each ion then calculate how many of each you will need in order for them to cancel out. E.g. Magnesium chloride - magnesium = 2+ and chloride = 1- so you need 2 chlorides for each magnesium.
2. An ion that is made up of more than one element.
3. Ions are arranged in a lattice; each ion is surrounded by ions of the opposite charge and they are held together by strong electrostatic forces.

Front 8

1. What are the properties of ionic compounds?
2. Explain why they have those properties.

Back 8

1. High melting and boiling points; can conduct electricity when molten or in aqueous solution but not when solid.
2. High melting and boiling points because they are held together by strong bonds which take a lot of energy to break. Only conduct electricity when molten or in aqueous solution because it is only then that the charged particles are free to move.

Front 9

1. What are the solubility rules for ionic compounds?
2. What is a precipitate?
3. What happens during a precipitation reaction?

Back 9

1. All common sodium, potassium and ammonium salts, nitrates, most chlorides (except lead and silver) and sulfates (except lead, barium and calcium)are soluble in water. Most carbonates (except sodium, potassium and ammonium) and hydroxides (except sodium, potassium and ammonium) are insoluble in water.
2. An insoluble soild formed during a precipitation reaction.
3. Two solutions of ionic compounds are mixed together and they swap partners. One of the new products is insoluble.

Front 10

1. What is a barium meal?
2. Why are they safe?
3. What are they used for?

Back 10

1. Barium sulfate is given to patients in a drink.
2. Barium sulfate is toxic but as it is insoluble it cannot be absorbed into the blood.
3. Barium sulfate is opaque to x-rays so it can be used to visualise the digestive system.

Front 11

1. Describe the test for cations.
2. Describe the test for carbonate ions.
3. Describe the test for chloride ions.
4. Describe the test for sulfate ions.

Back 11

1. Flame test. Put some of the sample on a wooden splint and hold it in a bunsen flame. The colour of the flame will change according to the cation present. Sodium: yellow; potassium: lilac; calcium: red; and copper: green/blue.
2. Add an acid to the salt, see if a gas is given off. Test the gas with lime water; if limewater turns cloudy it is carbon dioxide.
3. Add nitric acid and shake. Add silver nitrate, if a white precipitate forms it contains chloride ions.
4. Add drops of hydrochloric acid and shake. Add drops of barium chloride, if a white precipitate forms then sulfate ions are present.

Front 12

1. What is a covalent bond?
2. Between which types of atom do they form?
3. What do we call atoms joined by covalent bonds?
4. How do we represent covalent bonds in diagrams?
5. Why do atoms form covalent bonds?

Back 12

1. A pair of shared electrons.
2. Non-metals.
3. Molecules.
4. Dot-and-cross diagrams. Only outer shell electrons are drawn, one atom has crosses and one dots for electrons. Pairs of shared electrons are drawn in the space where the two circles overlap.
5. To make a full outer shell.

Front 13

1. What are the properties of simple covalent substances?
2. Why do they have these properties?
3. What are the properties of giant covalent substances?
4. Why do they have these properties?

Back 13

1. Low melting and boiling points, don't conduct electricity, usually gases at room temperature.
2. Although covalent bonds between atoms are strong the forces between molecules are weak and easy to break.
3. High melting and boiling points, hard.
4. Lots of strong covalent bonds joining atoms together to form giant lattice structures so lots of energy needed to break the bonds.

Front 14

1. Define the terms miscible and immiscible
2. How can immiscible liquids be separated?

Back 14

1. Miscible: two liquids that completely dissolve into each other. Immiscible: two liquids that don't dissolve into each other but separate into layers.
2. Use a separating funnel. Allow the liquids to form layers and turn on the tap to let the denser liquid out, close it before the second liquid comes out.

Front 15

1. What is chromatography used for?
2. How do you make a chromatogram?
3. How do you analyse chromatograms?
4. How do you calculate Rf values?

Back 15

1. To separate individual colours within a compound (eg. food colourings).
2. Draw a pencil line near the bottom of a piece of chromatography paper; put spots of the colours you are testing on the line; place the bottom of the paper (below the pencil line) into a solvent such as water; wait for the solvent to soak up the paper carrying the dye with it. Different dyes travel at different speeds so are separated.
3. Dots that are the same distance from the bottom must be the same colour dye.
4. distance moved by compound/distance moved by solvent

Front 16

1.Which types of substances dissolve in water?
2. What are the properties of metals?
3. What are metallic bonds?
4. How do metallic bonds explain the properties of metals?

Back 16

1. Most ionic compounds and some simple covalent substances. Giant covalent substances and metals do not dissolve in water.
2. Malleable, ductile, good conductors of heat and electricity; many form colourful compounds.
3. The type of bonding in metals. Positive metal ions are surrounded by a sea of electrons.
4. Metals are malleable because the layers of metal ions can slide over each other but are still held together by the sea of electrons. They can conduct electricity because these delocalised electrons are free to move.

Front 17

1. What are the metals in group 1 called?
2. Describe their reactivity and explain it.
3. What happens when they are put in water?
4. What is formed when they react with water?

Back 17

1. Alkali metals.
2. Very reactive because they only have one electron on their outer shell. They get more reactive as you move down the group because it is easier to lose the outer shell electron the further from the nucleus it is.
3. They float on the surface, fizz and move around. Potassium produces a lilac flame.
4. They produce a salt called a hydroxide (eg. sodium hydroxide) and hydrogen gas.

Front 18

1. What are the non-metals in group 7 called?
2. Describe their state at room temperature.
3.What do they form with metals?
4. Describe the order of reactivity of this group.
5. What happens when they react with hydrogen?

Back 18

1. Halogens.
2. Fluorine: clear gas; chlorine: yellow gas; bromine: brown liquid; iodine: grey solid.
3. Metal halides (eg. potassium bromide).
4. Get less reactive as you move down the group because it is harder to gain an electron the further the outer shell is from the nucleus.
5. Form hydrogen halides which dissolve in water to form acids.

Front 19

1. What are the gases in group 0 called?
2. Describe their reactivity.
3. Describe a use for helium, neon, argon and xenon.
4. How were they discovered?

Back 19

1. Noble gases.
2. They are very unreactive because they have full outer shells.
3. Helium: filling balloons; Neon: coloured lighting; argon: used in welding to protect the metal from oxygen in the air; xenon: used in filament lamps to stop the filament reacting with oxygen and burning away.
4. Chemists noticed that the density of nitrogen formed in experiments was different from that of nitrogen in the air and thought that there must be something else in air as well. They performed experiments to test this and discovered the noble gases.

Front 20

1. Define the terms exothermic and endothermic.
2. Explain them in terms of bonds being made and broken.
HIGHER ONLY
3. How are exothermic reactions shown in energy diagrams

Back 20

1. Exothermic: gives out heat energy.
Endothermic: takes in heat energy (so cools the surroundings).
2. Breaking bonds uses energy and making bonds releases energy. If more energy is used than is released then the reaction is endothermic (takes in energy). If more energy is released than is used then the reaction is exothermic (releases energy).
3. A horizontal line is drawn to represent the reactants and another is drawn below this to represent the products and to show that they have less energy than the reactants.

Front 21

1. Describe and explain the effect of each of these factors on reaction rates with reference to collision theory:
a. Temperature
b. Concentration
c. Surface area

Back 21

a. The higher the temperature the faster the reaction. This is because the particles have more energy so are moving faster and colliding more frequently.
b. The higher the concentration the faster the reaction. This is because there are more particles in a concentrated solution than in a dilute one so there are more collisions and therefore the reaction is faster.
c. The greater the surface area the faster the reaction. This is because there are more particles at the surface of the substance that are available to react so there are more collisions and a faster reaction.

Front 22

1. What do catalysts do?
2. What do catalytic converters in cars do?
3. How are they made to do this efficiently?

Back 22

1. They speed up reactions.
2. They increase the rate of reaction between carbon monoxide and unburnt fuel from exhaust gases with oxygen from the air to form carbon dioxide and water.
3. They have a honeycomb structure to increase their surface area and they work more efficiently when they are hot.

Front 23

1. How do you calculate relative formula mass?
2. How do you work out empirical formula?
3. How do you calculate percentage composition?

Back 23

1. Add together the relative atomic masses of every atom in the formula.
2. It is the simplest whole number ratio.
Mass of element/RAM (for all elements in compound)
Divide by smallest number to get ratio
3. Mass of element/ relative formula mass of compound x 100

Front 24

1. What is yield?
2. What is theoretical yield?
3. How do you calculate percentage yield?
4. Why is actual yield always less than theoretical yield?

Back 24

1. The amount of useful product formed in a reaction.
2. The maximum calculated amount of product that could be formed. Calculated from the relative formula mass of the product.
3. Actual yield/theoretical yield x 100
4. The reaction may be incomplete; some of the product may be lost during preparation (eg. when measuring); or there may have been unwanted reactions taking place at the same time as the wanted one.

Front 25

1. Why are waste products from chemical reactions a problem?
2. How do chemical companies ensure that they maximise their profits?

Back 25

1. They could cause environmental problems; be expensive to dispose of; or cause social problems in the area where the chemical plant is.
2. They ensure that the [percentage yield is high; that all products are useful so there is no waste; and make sure the reaction takes place as quickly as possible.

Front 26

HIGHER ONLY
5. Compare diamond and graphite.

Back 26

1. Diamond: very hard because each carbon is joined to 4 others by covalent bonds; doesn't conduct electricity because there are no free electrons. Graphite: soft because it forms in layers, bonds between atoms within layer are strong but bonds between layers are weak. Conducts electricity because one electron from each carbon atom is free to move.

Front 27

1. How can miscible liquids (eg. air) be separated?

Back 27

3. Fractional distillation. Cool the air so water and carbon dioxide freeze and can be removed. Cool it until it becomes liquid. Put the liquid into the bottom of the fractionating column, nitrogen has a higher boiling point than oxygen so it will evaporate and can be collected at the top of the column. Oxygen has a lower boiling point so it will remain a liquid and can be collected at the bottom of the column.