Periodic Table Group 7 (Halogens) Menu

Discusses trends in atomic radius, electronegativity, electron affinity and melting and boiling points of the Group 7 elements. It also looks at the bond strengths of halogen-halogen bonds and of hydrogen-halogen bonds.

Describes and explains the trend in oxidising ability of the Group 7 elements based on the reactions between one halogen and the ions of another one – for example, between Cl₂ and I^- ions from salts like KI.

The reactions of halogens with hydrogen, phosphorus, sodium, iron, iron(II) ions, and sodium hydroxide solution.

Discusses the acidity of the hydrogen halides (like hydrogen chloride), and explains why HF is a weak acid.

Describes and explains the trend in reducing ability of the halide ions based on their reactions with concentrated sulfuric acid.

Describes and explains the tests for halide ions using silver nitrate solution followed by ammonia solution.

Describes the manufacture of chlorine by the electrolysis of sodium chloride solution using a diaphragm cell and a membrane cell.