DP Chemistry (last assessment 2024)
Question 23M.3.HL.TZ2.26
| Date | May 2023 | Marks available | [Maximum mark: 4] | Reference code | 23M.3.HL.TZ2.26 |
| Level | HL | Paper | 3 | Time zone | TZ2 |
| Command term | Deduce, Explain | Question number | 26 | Adapted from | N/A |
26.
[Maximum mark: 4]
23M.3.HL.TZ2.26
Nuclear medicine can be used to diagnose and treat diseases.
(a)
Deduce the nuclear equation for the beta decay of cobalt-60.
[1]
Markscheme
✓
Accept “e/e-/β for beta particle.
Penalize incorrect Z even if elemental symbol is correct.
Penalize incorrectly placed A and Z on nuclear symbol.
Do not penalize missing Z on nuclear symbol.
(b)
Explain how Targeted Alpha Therapy (TAT) works and why it is used for treating cancers that have spread throughout the body.
[3]
Markscheme
radiation source delivered directly to cancer cells ✓
by a carrier drug/protein/antibody ✓
several sites in body can be targeted «at same time» ✓
Accept “radioisotope «selectively» absorbed by cancer cells” OR “targeted to cancer cells” for M1.
Reference to “cells” required in M1.
