Group 7

Question 1

Trend in Electronegativity going down the group

Answer 1

Decreases
Electrons in the shared pair are further from the nucleus
Increase shielding and atomic radius - larger atom
Weaker electrostatic attraction so less likely to attract the bonding pair

Question 2

Trend in boiling points going down the group

Answer 2

Increases
Increase in the size of the molecule
Increased strength of Van Der Walls forces
More energy required to overcome them

Question 3

Describe the colours of iodine

Answer 3

It’s a black/dark grey solid
Produces purple gas
Brown in solution

Question 4

Oxidising Power

Answer 4

Decreases down the group (Cl2 has highest oxidising ability)
Cl2 will displace Br- and I- ions
Br2 will displace I- ions
I2 won’t displace any halide ions