Key Stage 3 Science Book 1 Assessments
Elements compounds and reactions blue Answers
1. The Periodic Table shows chemical elements. Which one of these statements is untrue?
d)
Difficulty level: easy
Skill level: knowledge
2. Use your Periodic Table to classify these elements as metal, non-metal or metalloid. [1 mark]
Sodium (Na)
Metal
Aluminium (Al)
Metal
Silicon (Si)
Metalloid
Sulfur (S)
Non-metal
Argon (Ar)
Non-metal
Difficulty level: easy
Skill level: knowledge
3. Why is gold sometimes used in circuit boards? [1 mark]
c)
Difficulty level: easy
Skill level: knowledge
4. This picture shows a flame test being carried out:
The scientist then uses a key to identify the element.
Which is it? [1 mark]
b)
Difficulty level: easy
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Key Stage 3 Science Book 1 Assessments
Skill level: evaluation
5. Water has the chemical formula H2O. Explain what the formula H2O means. [2 marks]
(the answer should contain the following)
1) Water contains [the elements] hydrogen and oxygen
2) Hydrogen and oxygen combine in the ratio 2:1
Difficulty level: moderate
Skill level: knowledge
6. In Diagrams A, B and C the circles represent two different types of atom. What does Diagram A show? [1 mark]
b)
Difficulty level: easy
Skill level: application
7. In Diagrams A, B and C the circles represent two different types of atom. What does Diagram C show? [1 mark]
c)
Difficulty level: easy
Skill level: application
8. Bromine is a liquid at room temperature. Fill in the gaps in the sentences below by using the words ‘above’ or
‘below’. [2 marks]
The melting point of bromine is below room temperature.
The boiling point of bromine is above room temperature.
© HarperCollinsPublishers 2014
Key Stage 3 Science Book 1 Assessments
9. Describe what is happening when magnesium burns in air. [4 marks]
(the answer should contain any four of the following)
1) It burns quickly
2) It reacts with oxygen from the air
3) Magnesium atoms combine with oxygen atoms
4) It produces magnesium oxide/a white powder
5) magnesium + oxygen  magnesium oxide
6) It’s an irreversible change
Difficulty level: easy
Skill level: application
10. The formula of a chemical compound can be modelled using building bricks. Match these diagrams of building
blocks to compounds they model. [4 marks]
Diagram A
Carbon dioxide (CO2)
Diagram B
Copper oxide (CuO)
Diagram C
Methane (CH4)
Diagram D
Aluminium chloride (AlCl3)
Difficulty level: moderate
Skill level: application
© HarperCollinsPublishers 2014
Key Stage 3 Science Book 1 Assessments
11. Sulfur is a yellow solid. It burns in air to form a poisonous acidic gas called sulfur dioxide. Use this information
to fill in the blanks in the sentence below.
In this chemical reaction, sulfur and oxygen are reactants, and sulfur dioxide is a product. [2 marks]
Difficulty level: easy
Skill level: knowledge
12. Gold is an element which is usually found it its native state. It is often found in small amounts in river
sediments.
Explain how gold can be separated from river sediments. [4 marks]
(the answer should contain any four of the following)
1) By panning
2) Sediments are put in a pan with water
3) River sediments are washed away with water
4) Gold is much denser than the sediments
5) The gold stays in the pan
Difficulty level: easy
Skill level: knowledge
13. Look at the bar chart. It shows the densities of the group 18 elements (noble gases).
The density of Krypton hasn’t been entered. Which of these values for the density of krypton is most likely to be
accurate? [1 mark]
a)
Difficulty level: easy
Skill level: evaluation
© HarperCollinsPublishers 2014
Key Stage 3 Science Book 1 Assessments
14. Look at the data table for the group 18 elements (noble gases).
How does the density of the noble gases change as you go down the group? [1 mark]
b)
Difficulty level: easy
Skill level: evaluation
15. Look at the data table for the group 18 elements (noble gases).
Suggest the most likely state for argon at -190OC. [1 mark]
b)
Difficulty level: easy
Skill level: evaluation
16. Look at the data table for the group 18 elements (noble gases).
How do the boiling points of the noble gases change as you go down the group? [1 mark]
a)
Difficulty level: easy
Skill level: evaluation
© HarperCollinsPublishers 2014
Key Stage 3 Science Book 1 Assessments
17. Look at the data table for the group 18 elements (noble gases).
Suggest a likely value for the boiling point of krypton. [1 mark]
b)
Difficulty level: moderate
Skill level: evaluation
18. A group of students reacted magnesium metal in air to make magnesium oxide. The students weighed the
magnesium before the experiment and weighed the mass of magnesium oxide after the experiment.
They repeated the experiment three more times.
Why was it important to repeat the experiment? [1 mark]
b)
Difficulty level: moderate
Skill level: knowledge
© HarperCollinsPublishers 2014