Predicting Chemical Reactions (OCR GCSE Chemistry A (Gateway))

This question is about elements in the Periodic Table.

Look at the table. It shows some properties of Group 7 elements.

Complete the table. Use ideas about trends down a Group to help you.

In the table, the Group 7 elements are listed in order of reactivity.

The equations show a displacement reaction of Group 7 elements.

chlorine + sodium bromide → sodium chloride + bromine
Cl₂        +         2NaBr           →              2NaCl     +     Br₂

i) Complete the word equation.

bromine + sodium iodide → ................... + ...................

[1]

ii) There is no reaction between iodine and sodium bromide.

Explain why.

[1]

iii) Chlorine reacts with sodium iodide. Sodium chloride and iodine are made.

Write the balanced symbol equation for this reaction.

[2]

Group 1 is another group of elements in the Periodic Table.

i) Potassium is a Group 1 metal.

Potassium is stored under oil because it is very reactive.

What does the oil stop the potassium reacting with?

[1]

ii) Sodium is another Group 1 metal.

Sodium reacts in a similar way to potassium.

Explain why.

Use ideas about atomic structure in your answer.

[1]

This question is about the properties of elements in Groups 1, 7 and 0.

Lithium, sodium and potassium are all Group 1 elements.

A teacher adds a small piece of potassium to a trough of water, as shown in the diagram.

The potassium fizzes and a gas is produced.

Describe what else you would observe.

Reactivity increases going down Group 1 from lithium to potassium.

Explain this trend in reactivity.

Use ideas about the electronic configurations of the atoms in your answer.

Look at the table. It shows information about the Group 7 elements.

Complete the table.

The Group 7 elements exist as simple molecules.

Fluorine boils at −188°C.

Explain why fluorine has a low boiling point.

The elements in Group 0 (the noble gases) are unreactive.

Explain why, in terms of their electronic configurations.