Group 7(17), the halogens

Question 1

The appearance of Fluorine:

Answer 1

Very pale yellow gas. It is highly reactive

Question 2

The appearance of Chlorine:

Answer 2

Greenish, reactive gas, poisonous in high concentrations

Question 3

The appearance of Bromine:

Answer 3

Red liquid, that gives off dense brown/orange poisonous fumes

Question 4

The appearance of Iodine:

Answer 4

Shiny grey solid sublimes to purple gas.

Question 5

Trend in melting point and boiling point in G7.

Answer 5

Increase down the group

As the molecules become larger they have
more electrons and so have larger Van der
Waals forces between the molecules. As the
intermolecular forces get larger more energy
has to be put in to break the forces.

Question 6

Trend in electronegativity in G7.

Answer 6

Decreases down the group

The atomic radius gets bigger so it increases the distance between the bonding pair and the nucleus.

Question 7

The trend in bond strength in G7.

Answer 7

Decreases down the group

The electron pair is further away from the nucleus
therefore there is a weaker attraction between the nucleus and the bonding pair.

Question 8

How are G7 elements oxidising agents?

Answer 8

They gain an electron when they react.

A halogen that is a strong oxidising agent will
displace a halogen that has a lower oxidising
power from one of its compounds.

Question 9

The ability to oxidise decreases down Group 7. Why is this the case?

Answer 9

The smaller the halogen the easier it is to gain an electron.

This can be done by decreasing the distance between the nucleus and the outer shell

Less shielding with a smaller atom.