BRAINCAKEHalogens
Group 7 elements are called the Halogens. They are all diatomic molecules and the melting temperature increases down the group. When two molecules are close together they experience London forces (instantaneous dipole-induced dipole forces). As you go down the group there are more electrons so there are stronger London forces and the melting point increases. The halogens exist as diatomic molecules X2 at room temperature and pressure.
Fluoride is added to drinking water and toothpaste to prevent tooth decay.
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Key terms in this lesson
- Dipole
- A separation of opposite partial charges caused by an uneven distribution of the bonding electron pair.
- London forces
- Weak intermolecular forces caused by instantaneous dipoles inducing dipoles in neighbouring molecules.
- Group
- A vertical column of the periodic table, containing elements with the same number of outer-shell electrons.
More in Group 7
- Physical Properties
- Size of Atoms
- Electronegativity
- Melting and Boiling Points
- Trends in Oxidising Ability
- Displacement Reactions
- Halide Ions as Reducing Agents
- Sodium Chloride with Sulfuric Acid
All 16 lessons in Group 7 · All AQA AS-level Chemistry topics