Group 2 elements combine with chlorine when heated in the gas.The reaction becomes more vigorous down the group.The general equation for the reaction is:M (s) + Cl2 (g) → M Cl2 (s)For example, heated magnesium reacts with chlorine to form magnesium chloride:Mg (s) + Cl2 (g) → MgCl2 (s) The products are white ionic solids containing M2+ and Cl− ions. They dissolve in water to give colourless solutions.This is a redox reaction. The metal is oxidised from 0 to +2 and chlorine is reduced from 0 to −1:M → M2+ + 2 e−
Cl2 + 2 e− → 2 Cl− The group 2 metal is the reducing agent and chlorine is the oxidising agent.The reaction becomes more vigorous down the group because the sum of the first and second ionisation energies decreases. The atoms lose their two outer electrons more easily, so barium reacts faster than magnesium.
Reactions with Chlorine
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Specification: Edexcel Chemistry (8CH0), AS-level, Topic 4A: The elements of Groups 1 and 2. Topic: Group 2.
Key terms in this lesson
- reducing agent
- A substance that donates electrons to another species, causing it to be reduced, while it is itself oxidised.
- oxidising agent
- A substance that accepts electrons from another species, causing it to be oxidised, while it is itself reduced.
- ionisation energy
- The energy needed to remove one electron from each atom in one mole of gaseous atoms, forming one mole of gaseous 1+ ions.
More in Group 2
- Group 2 Elements
- Trend In Ionisation Energy
- Trend in Reactivity
- Reactions with Oxygen
- Reactions with Water
- Magnesium and Steam
- Reactions of Oxides with Water
- Trends in Solubility of the Hydroxides
All 16 lessons in Group 2 · All Edexcel AS-level Chemistry topics