DP Chemistry (last assessment 2024)
Question 18M.2.sl.TZ2.6a.i
| Date | May 2018 | Marks available | [Maximum mark: 2] | Reference code | 18M.2.sl.TZ2.6a.i |
| Level | sl | Paper | 2 | Time zone | TZ2 |
| Command term | Explain | Question number | a.i | Adapted from | N/A |
a.i.
[Maximum mark: 2]
18M.2.sl.TZ2.6a.i
Some physical properties of molecular substances result from the different types of forces between their molecules.
(a.i)
Explain why the hydrides of group 16 elements (H2O, H2S, H2Se and H2Te) are polar molecules.
[2]
Markscheme
polar bonds «between H and group 16 element»
OR
difference in electronegativities «between H and group 16 element»
uneven distribution of charge/electron cloud
OR
non-linear/bent/V-shaped/angular shape «due to lone pairs»
OR
polar bonds/dipoles do not cancel out
M2:
Do not accept “net/overall dipole moment” without further explanation.
Accept “non-symmetrical «shape/distribution of charge»”.
[2 marks]