Question 19M.3.hl.TZ1.1b(i)
| Date | May 2019 | Marks available | [Maximum mark: 1] | Reference code | 19M.3.hl.TZ1.1b(i) |
| Level | hl | Paper | 3 | Time zone | TZ1 |
| Command term | Describe | Question number | b(i) | Adapted from | N/A |
Physical properties of elements vary according to atomic number. Sections 6 to 9 of the data
booklet list some of these properties.
Melting points and boiling points of elements 1 to 95
Describe the density trend across periods 4 and 5 of the periodic table.
[1]
density increases «to a maximum in the transition elements» AND then decreases [✔]
Required candidates to consider density trends. Most candidates correctly described trends across periods 4 and 5 but had difficulty predicting and explaining whether lanthanoids or actinoids would have the higher density. Many said that actinoids would have higher density because they have more protons and neutrons / greater atomic number / greater mass with no further detail about having similar bonding and hence similar volume. Some G2 comments complained about the inclusion of lanthanoids and actinoids in this question. However, the Chemistry Guide clearly states that these terms should be known.
