# Potassium is an alkali metal. When a small piece of potassium is placed on the surface of water, a reaction occurs. State the name of the gas produced and the name of the solution formed. Then explain why potassium reacts more vigorously with water than lithium does.

> Pearson Edexcel International GCSE Chemistry (4CH1) — 2.1 Group 1 (alkali metals) · State · 4 marks

> Alkali metals are the elements in Group 1 of the periodic table. They are typically soft and have relatively low melting points. They react with water to produce an alkaline solution.

## Mark scheme (4 marks)

1. Hydrogen (gas) is produced
2. Potassium hydroxide solution is formed
3. Potassium has more electron shells / its outer electron is further from the nucleus than lithium's
4. Therefore the outer electron is lost more easily (in potassium than in lithium)

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