DP Chemistry (first assessment 2025)
Question 22M.1A.HL.TZ1.8
| Date | May 2022 | Marks available | [Maximum mark: 1] | Reference code | 22M.1A.HL.TZ1.8 |
| Level | HL | Paper | 1A | Time zone | TZ1 |
| Command term | State | Question number | 8 | Adapted from | N/A |
8.
[Maximum mark: 1]
22M.1A.HL.TZ1.8
Why is hydrated copper (II) sulfate blue?
A. Blue light is emitted when electrons return to lower d-orbitals.
B. Light complimentary to blue is absorbed when electrons return to lower d-orbitals.
C. Blue light is emitted when electrons are promoted between d-orbitals.
D. Light complimentary to blue is absorbed when electrons are promoted between d-orbitals.
[1]
Markscheme
D
Examiners report
Higher scoring candidates managed to identify why hydrated copper(II) sulfate is blue in colour.
Syllabus sections
Structure 3. Classification of matter » Structure 3.1—The periodic table: Classification of elements » Structure 3.1.10—Transition element complexes are coloured due to the absorption of light when an electron is promoted between the orbitals in the split d-sublevels. The colour absorbed is complementary to the colour observed. Apply the colour wheel to deduce the wavelengths and frequencies of light absorbed and/or observed.