DP Chemistry (first assessment 2025)
Question 19M.2.SL.TZ2.4d
| Date | May 2019 | Marks available | [Maximum mark: 2] | Reference code | 19M.2.SL.TZ2.4d |
| Level | SL | Paper | 2 | Time zone | TZ2 |
| Command term | Outline | Question number | d | Adapted from | N/A |
d.
[Maximum mark: 2]
19M.2.SL.TZ2.4d
(d)
Outline how alloys conduct electricity and why they are often harder than pure metals.
Conduct electricity:
Harder than pure metals:
[2]
Markscheme
Conduct electricity:
«delocalized/valence» electrons free to move «under potential difference» [✔]
Harder than pure metals:
atoms/ions of different sizes prevent layers «of atoms/ions» from sliding over one another [✔]
Examiners report
Most candidates were awarded one mark for how alloys conduct electricity. Some struggled with describing why they are harder than pure metals.
