Group 7 Elements

Question 1

The Halogens are Non-Metals but what colour vapour does each Halogen have?

Answer 1

Fluorine is a very reactive, poisonous yellow gas
Chlorine is a fairly reactive, poisonous dense green gas
Bromine is a dense, poisonous, red-brown volatile liquid
Iodine is a dark grey crystalline solid or a purple vapour

They all exist as molecules which are pairs of atoms.

Question 2

Learn These TRENDS:

Answer 2

As you go DOWN Group 7, the Halogens:

become less reactive - it’s harder to gain an extra electron, because the outer shell’s further from the nucleus.
have higher Melting and Boiling Points.
have higher Relative Atomic Masses

Question 3

Will more reactive Halogens displace Less Reactive Ones?

Answer 3

Yes

A displacement reaction can occur between a more reactive halogen and the salt of a less reactive one. E.g. Chlorine can displace Bromine and Iodine from an aqueous solution of its salt ( a bromide or Iodide). Bromine will also displace Iodine because of the trend in Reactivity.