C8.3 Group VII properties

Describe characteristics of the halogens

• Group 7 elements

• 7 electrons in the outer shell (1- charge)

  • Form halide ions

• Diatomic non-metals

• Halogens are poisonous

• Moving down the group they go from lighter to darker color

Describe group VII trends relating to increasing density

• The density of halogens increases going down the group

Describe group VII trends relating to decreasing reactivity

• As you go down the group, reactivity decreases

• Atomic radius increases (or there are more electron shells)

• There is weaker attraction between the nucleus and the outer electron

• It is harder to gain and attract electrons

Explain the displacement of halogens in reactions

• Since reactivity decreases as you go down the group, the more reactive halogen replaces the less reactive one

What are the appearance of halogens at r.t.p?

1. Chlorine: a pale yellow-green gas

2. Bromine: a red-brown liquid

3. Iodine: a grey-black solid