# Magnesium, calcium, strontium and barium are all Group 2 metals. When these metals react with dilute hydrochloric acid, a salt and hydrogen gas are produced. Explain how and why the vigour of this reaction changes as you move down Group 2 from magnesium to barium.

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

> Group 2 metals all react with dilute hydrochloric acid. The general equation for these reactions is: M + 2HCl → MCl₂ + H₂, where M represents a Group 2 metal.

## Mark scheme (5 marks)

1. The vigour of the reaction increases going down the group (from magnesium to barium)
2. Each successive element has one more electron shell / larger atomic radius going down the group
3. The outer electrons experience greater shielding from the nucleus going down the group
4. The electrostatic attraction between the nucleus and the outer electrons decreases going down the group
5. Outer electrons are lost more easily, so the metal forms cations more readily / is more reactive

## Key terms

- [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)
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Source: [GradeNine](https://www.gradenine.co.uk/q/magnesium-calcium-strontium-and-barium-are-fe67b264) · Published by Druglandscape Ltd.