•Discuss the similarities and differences in the chemical properties of elements in the same group

Chem. Properties of groups Chem. Properties of groups3.3.1

What is the reactivity of the halogens?

The reactions of the halogens with iron and hydrogen show that their reactivity decreases down the group.

How do you think fluorine and astatine would react with iron wool and hydrogen?

Iron wool burns and glows brightly.

Iron wool has a very slight glow.

Iron wool glows but less brightly than with chlorine.

chlorine

bromine

iodine

Halogen Reaction with iron wool Reaction with hydrogen

Explodes in sunlight, reacts slowly in the dark.

Reacts slowly on heating with catalyst.

Reacts partially and very slowly.

Reactions of the halogens

Halogens react with metals such as sodium and iron:

They also take part in displacement reactions with halide ions, such as the reaction that is used to make bromine from potassium bromide in seawater:

halogen + hydrogen hydrogen halide

They also react with non-metals such as hydrogen:

halogen + sodium sodium halide

chlorine +potassiumbromide

potassiumchloride bromine +