Year 8 Chemistry. Pre-Test Revision Questions
1. Tick the correct box to complete the sentence. The elements in the Periodic Table are arranging in order of
increasing:
[1]
□
□
□
□
Number of atoms
Neutron number
Relative atomic mass
Atomic number
2. State the number of protons, electrons and neutrons in an atom of Na [3]
Protons: ____________________________11
Electrons: ____________________________11
Neutrons: ____________________________12
3. Complete the table to show the relative masses, charge and location of the three sub atomic particles. [3]
Particle
Proton
Electron
Neutron
Relative Mass
1
1/1860
1
Charge
+
Negative
Neutral
Location
Nucleus
In shells
Nucleus
4. Why does an atom of sodium have no overall charge? [1]
Same number of protons and electrons (same number of positive and negative particles)
________________________________________________________________________________________
5. Draw a diagram to show the electron arrangement of an ATOM of sodium. [1]
6. Draw a diagram to show the electron arrangement of an ION of sodium. Ensure you include the charge. [2]
7. Sodium, lithium and potassium all have similar chemical properties. Explain by referring to the electron
arrangement, why elements in the same group of the periodic table have similar chemical properties. [1]
Elements in the same group have the same number of electrons in the outer shell
________________________________________________________________________________________
8. Group one metals will react with water. State 2 observations you could make when the following Group
one metals are added to water: [6]
a) Potassium - lilac flame, floats, dissolves, fizzing/bubbles
b) Sodium - melts into a silver ball, fizzing/bubbles, dissolves
c) Lithium – floats, fizzes and dissolves
d) Write a balanced chemical equation for the reaction between potassium and water. [2]
2K + 2H20  2KOH + H2
e) Which product of the reaction is an alkali and therefore will turn universal indicator solution
blue? [1]
KOH (potassium hydroxide)
9. Sodium can react with different elements to form a variety of compounds. One compound is sodium
sulphate, which has the formula Na2SO4
i) How many different atoms are present in Na2SO4
3 ( Na, S and O)
[1]
ii) What is the total number of atoms in Na2SO4
7
[1]
10. Elements can exist in three different states of matter.
a) Complete the diagrams in the boxes to show the arrangement of particles when the substance is a solid,
liquid and a gas. [6]
b) Which state will have the highest density of particles? Explain your answer
[2]
Solid. (1) Particles are more closely packed together/ particles are closer together /more particles in
the tank (must be a comparison) (1)
11. Use your periodic table and data sheet. Write the formula of the following compounds. Remember,
compounds are electrically neutral. (The combining powers/valencies of the ions must cancel to 0)
[4]
a) calcium oxide
CaO
b) lithium phosphide
Li3P
c) magnesium fluoride MgF2
d) sodium carbonate
Na2CO3
e) Lithium oxide
Li2O
12. A small amount of calcium oxide is dissolved in water. When universal indicator is added to the solution,
the indicator turns blue. What does the observation with the indicator show about calcium oxide?
[1]
It is an alkali / base or forms an alkaline solution
13. When calcium oxide is added to water, heat energy is released and the temperature of the surroundings
increases. What is the name given to this type of reaction? Exothermic
[1]
14. The reactivity of metals can be studied using displacement reactions. In these reactions, one metal is
added to a solution of a salt of a different metal.
 If a displacement reaction occurs, there is a temperature rise.
A student used the following method in a series of experiments.



Pour some metal salt solution into a polystyrene cup supported in a glass beaker and record the
temperature of the solution
Add a known mass of a metal and stir
Record the maximum temperature of the mixture
a) The student used a thermometer to measure the temperature rise. The diagrams show the
thermometer readings before and after adding the metal.
Use the diagrams to complete the table.
[3]
22.2
17.5
4.7



The student used copper sulphate solution in all her experiments.
She used five different metals. She did not know the identity of the metal labelled ‘X’
The student did each experiment twice. The table shows her results.
b) Which of the metals gave the least reliable temperature rise? Explain your choice.
Metal: Mg
[2]
Explanation: Biggest difference between the temperature rise in run 1 and run 2
c) Identify the most reactive of the metals used. Explain how the results show that it is the most reactive [2]
Metal: Mg
Explanation: Greatest average temperature rise
d) Why is there no temperature rise when silver is added to copper sulphate solution?
[2]
No displacement reaction occurred /silver not reactive enough to displace copper from the copper
sulphate
e) Why do the results make it impossible to decide which of the metals is the least reactive?
Both silver and metal ‘x’ show no temperature rise
[1]
f) A word equation for one of the reactions is:
zinc + copper sulphate  copper + zinc sulphate
Write a chemical equation for this reaction
[2]
Zn + CuSO4  Cu + ZnSO4
15. Like other metals, iron is malleable, ductile, has a high melting point and is a good conductor of electricity.
a) Draw a labelled diagram to show the bonding in iron metal.[2] (include the key terms: delocalised electrons
and positive ions)
b) What is meant by the term ‘malleable’? [1]
‘can be bent/hammered’ into shape
c) Explain why iron is a good conductor of electricity. [2]
Iron has delocalised electrons which can move throughout the structure (when a voltage is applied)
d) Explain why iron is ductile. [2]
The metal ions/atoms form regular layers, which can slide over each other (when a force is applied)
16. Write a chemical equation for the following ‘MASH’ reactions: [2]
a) Magnesium + Sulphuric Acid  Magnesium Sulphate + Hydrogen
Mg + H2SO4  MgSO4 + H2
b) Iron + Hydrochloric Acid  Iron Chloride + Hydrogen (the formula for Iron Chloride is FeCl2)
Fe + 2HCl  FeCl2 + H2
17.
a) Complete the paragraph, using the words in bold
electricity
iron
compound
[5]
elements
bromine
Electrolysis is the splitting up of a compound into its elements using electricity . In the electrolysis of
iron bromide solution, pure iron and bromine is produced.
b) What is the name of FeBr2?
[1]
c) What ions are present in FeBr2? [1]
Iron Bromide
Fe2+ and Br- (two Br-)
d) Complete the half equations to show what is happening to the ions during the electrolysis of
FeBr2 [2]
Fe2+ + 2e Fe
2Br- - 2e  Br2
e) Which of the reactions in d) shows oxidation? Explain your answer. (think OIL RIG) [2]
2Br- - 2e  Br2 as Br- (bromide) has lost electrons to form bromine. Oxidation means
the loss of electrons