Group VII, Halogens

Question 1

Halogen or halide?

Answer 1

A halogen is one of the group 7 elements, X, while a halide ion is a halogen in -1 oxidation state, X^-1

Question 2

Structure of halogens

Answer 2

Form diatomic bonds (X2)Simple molecular, with weak IMF between molecules.

Question 3

Halogen appearance in pure form

Answer 3

Fluorine- pale yellow gas
Chlorine- pale green gas
Bromine- dark red liquid
Iodine- Grey solid

Question 4

Halogen appearance in non-polar solvents

Answer 4

Fluorine- reacts with solvent
Chlorine- pale green solution
Bromine- orange solution
Iodine- purple solution

Question 5

Halogen appearance in water

Answer 5

Flourine- reacts with water
Chlorine- Pale green solution
Bromine- orange solution
Iodine- Insoluble, but sometimes forms a brown solution of I3- if Iodide ions are present

Question 6

Melting/boiling point trend of halogens

Answer 6

Temperatures increase as you go down the group, due to the increase of Van der Waals

Question 7

Electronegativity trend of halogens

Answer 7

Decreases down the group as more shells means more shielding and distance from the nuclear charge

Question 8

Properties of halogens

Answer 8

Oxidising agents, decreasing down the group

Question 9

Properties of halides

Answer 9

Reducing agents, increasing down the group

Question 10

Displacement of halogens

Answer 10

The more reactive halogens (strongest oxidising agents) will displace the more reactive halides (strongest reducing agents) from solutions of their ions

Question 11

Displacement of bromide by chlorine

Answer 11

Cl2+2Br- —> Br2+2Cl-

Orange colour will appear in solution

Question 12

Displacement of iodide by chlorine

Answer 12

Cl2+2I- —> I2+2Cl-

Brown colour will appear in solution

Question 13

Displacement of iodide by bromine

Answer 13

Br2+2I- —>I2+2Cl-

Brown colour will appear in solution