module 3: 8.1 group 2

Question 1

Is a group 2 metal oxidised or reduced

Answer 1

Oxidised
E.g. Ca —> Ca2+ + 2e-
It is a reducing agent

Question 2

Group 2 reactions with oxygen. What is oxidised what is reduced?

Answer 2

2Mg + O2 —> 2MgO
Mg is oxidised: 0 —> +2 total increase = +4
O is reduced: 0 —> -2 total increase = -4

Question 3

Group 2 reaction with water. What is oxidised and reduced?

Answer 3

Sr + 2H2O —> Sr(OH)2 + H2
Sr is oxidised: 0 —> +2. Total increase of +2
H is reduced: 0 —> -2. total increase of -2

Question 4

Group 2 reactions with dilute acid. What is oxidised and reduced?

Answer 4

Metal + acid —> salt + hydrogen
Mg + 2HCl —> MgCl2 + H2
Mg is oxidised. 0 —> +2
H is reduced. +1 —> 0

Question 5

First and second ionisation energy with group 2 metal reaction

Answer 5

M(g) —> M+ (g) + e-

M+ (g) —> M2+ (g) + e-

Question 6

First ionisation energy definition

what are factors that affect the first ionisation energy

Answer 6

the removal of one mole of electrons from one mole of gaseous
atoms.
Factors that affect the first ionisation energy are:
the strength of attraction between the electron and the nucleus,
the nuclear charge
and the atomic radius.

Question 7

Describe the trend in reactivity down group 2

Answer 7

increases as it goes down the group:

more reactive and stronger reducing agents down the group

Question 8

describe what happens to the ionisation energy levels as you go down the group 2

Answer 8

ionisation energy decreases
the attraction between the nucleus and outer electrons decrease
increase atomic radius
increase in shielding

Question 9

solubility of hydroxides down group 2

Answer 9

increases down group 2

this means that the solutions contain more OH- ions and are more alkaline