# Beryllium (Be), magnesium (Mg), calcium (Ca) and barium (Ba) are all Group 2 metals. Each metal reacts with dilute hydrochloric acid to form a metal chloride and hydrogen gas. Using your knowledge of the reactivity series and Group 2 trends, explain why barium reacts more vigorously with dilute hydrochloric acid than magnesium does, and predict what you would observe during the reaction of barium with dilute hydrochloric acid.

> Edexcel A-Level Chemistry (9CH0) — 4.1 Group 2 metals · Explain · 5 marks

> Group 2 metals react with dilute hydrochloric acid. The reactivity of Group 2 metals increases down the group.

## Mark scheme (5 marks)

1. Barium is lower/further down Group 2 than magnesium
2. Barium atoms have more electron shells / the outer electron is in a higher energy shell / the outer electron is further from the nucleus
3. The outer electron is more easily lost / less energy is needed to remove the outer electron (because there is greater shielding / weaker nuclear attraction on the outer electron)
4. Barium is higher in the reactivity series than magnesium / barium is more reactive than magnesium
5. A correct observation for barium reacting with dilute hydrochloric acid: e.g. bubbles/effervescence produced rapidly / barium dissolves quickly / the reaction is faster/more vigorous than magnesium

## Key terms

- [reactivity series](https://www.gradenine.co.uk/glossary/reactivity-series)
- [Group 2](https://www.gradenine.co.uk/glossary/group-2)

## Related

- [Revision notes for Edexcel A-Level Chemistry (9CH0)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/beryllium-be-magnesium-mg-calcium-ca-2576d203) · Published by Druglandscape Ltd.