Group 7 - the Halogens

Question 1

Displacement

Answer 1

A chemical reaction in which one element replaces another element in a compound. A halogen will displace a halide from solution if the halide is below it in the periodic table

Question 2

Disproportionation

Answer 2

A reaction in which a substance is simultaneously reduced and oxidised. Chlorine undergoes disproportionation in the reaction with cold, dilute, aqueous sodium hydroxide

Question 3

Electronegativity

Answer 3

The tendency of an atom to attract a bonding pair of electrons

Question 4

Oxidising ability

Answer 4

Oxidising ability is the ability to act as an oxidising agent. The oxidising ability of the halogens decreases down the group.
This is because down the group the atoms get larger so the electrons are less strongly attracted to the nucleus so it is harder to gain an electron

Question 5

Redox reaction

Answer 5

A reaction in which oxidation and reduction occur simultaneously

Question 6

Reducing ability

Answer 6

Reducing ability is the ability to act as a reducing agent. The reducing ability, or reducing power, of the halides increases down the group. This is because to act as a reducing agent the halide needs to lose an electron.
As you go down the group it is easier for a halide to lose an electron because the attraction form the outer electron and nucleus decreases due to increased shielding and an increasing ionic radius