group 7 ( halogens )

why does boiling point increase down group 7

as the outer shells increase, intermolecular forces between molecules get stronger so more energy is required to break these forces so boiling point increases

Group 7 properties

• Non-metals.

• Exist as diatomic molecules (Cl₂, Br₂, etc.).

• Form -1 ions.

Physical state of fluorine room temp

pale yellow , gas

Physical state of chlorine room temp

Pale green , gas

Physical state of bromine room temp

red - brown , liquid

Physical state of Iodine room temp

dark grey , solid

Physical state of Astatine room temp

Black , solid

Why does reactivity decrease down the group

Halogens gain electrons

Down the group:

• atoms get larger and gain extra electron shells, making it harder for the nucleus to attract an incoming electron due to the extra distance and shielding from the nucleus