DP Chemistry (last assessment 2024)
Question 18M.3.sl.TZ2.1b
| Date | May 2018 | Marks available | [Maximum mark: 2] | Reference code | 18M.3.sl.TZ2.1b |
| Level | sl | Paper | 3 | Time zone | TZ2 |
| Command term | Justify, Suggest | Question number | b | Adapted from | N/A |
b.
[Maximum mark: 2]
18M.3.sl.TZ2.1b
The table summarizes some properties of graphite and graphene.
(b)
Diamond, graphene, and graphite are all network solids.
Suggest, giving a reason, the electron mobility of diamond compared to graphene.
[2]
Markscheme
smaller/zero
no delocalized electrons/electrons are bound/electrons not free to move/electrons not free to roam
OR
localized electrons «in sigma bonds»
OR
large band gap
Accept “diamond is a dielectric” OR “diamond does not conduct electricity” for M2.
Award [1 max] for just “immobile/less mobile”.
Award [2] for “electrons immobile «in diamond» due to the large band gap” OR "electrons «in diamond» immobile
since electrons are localized «in the sigma bonds»”.
[2 marks]
