Question 22M.2.hl.TZ1.4e
| Date | May 2022 | Marks available | [Maximum mark: 2] | Reference code | 22M.2.hl.TZ1.4e |
| Level | hl | Paper | 2 | Time zone | TZ1 |
| Command term | Compare and contrast | Question number | e | Adapted from | N/A |
Ammonia is soluble in water and forms an alkaline solution:
NH3 (g) + H2O (l) NH4+ (aq) + HO– (aq)
Mg(OH)+ is a complex ion, but Mg is not regarded as a transition metal. Contrast Mg with manganese, Mn, in terms of one characteristic chemical property of transition metals, other than complex ion formation.
[2]
ALTERNATIVE 1
Property: variable oxidation state ✔
Comparison: Mn compounds can exist in different valencies/oxidation states AND Mg has a valency/oxidation state of +2 in all its compounds ✔
Accept valency.
Accept for second statement “Mg «always» has the same oxidation state”.
ALTERNATIVE 2
Property: coloured ions/compounds/complexes ✔
Comparison: Mn ions/compounds/complexes coloured AND Mg ions/compounds white/«as solids»/colourless «in aqueous solution» ✔
Accept Mn forms coloured ions/compounds/complexes and Mg does not.
ALTERNATIVE 3
Property: catalytic activity ✔
Comparison: «many» Mn compounds act as catalysts AND Mg compounds do not «generally» catalyse reactions ✔
For any property accept a correct specific example, for example manganate(VII) is purple.
Do not accept differences in atomic structure, such as partially filled d sub-levels, but award ECF for a correct discussion.
