Question 19N.3.hl.TZ0.27

Any two of:
hair loss
fatigue
nausea
sterility
skin reaction
diarrhoea
vomiting
damage to lymph system
urinary/bladder changes
anxiety/emotional problems
joint/muscular stiffness
loss of appetite
sore/dry mouth
loss of weight
secondary cancer ✔

Any two of:
half-life is 6 hours/long enough for a scan to occur
OR
half-life short enough not to remain in body ✔
NOTE: Accept “short half-life so patient is not exposed to lots of ionizing radiation”.

decay releases «low energy» gamma rays
OR
gamma rays less likely to be absorbed by cells ✔

can form several «coordination» complexes ✔
NOTE: Accept "can exist in many oxidation states «so can form multiple complexes»" OR "chemically versatile «so can act as a tracer by bonding to several bioactive compounds»”.

«low-energy» radiation/gamma-rays can be detected by common X-ray equipment ✔

ALTERNATIVE 1
4 half-lives ✔
1.56 «μg of iodine-131 remain» ✔

ALTERNATIVE 2
m = 25.0 ${\left(\frac{1}{2}\right)}^{\frac{32.0}{8.00}}$ ✔
1.56 «μg of iodine-131 remain» ✔

ALTERNATIVE 3
λ = « $\frac{\ln 2}{8.00}$ » = 8.66 × 10⁻² «day⁻¹» ✔
m = « $25.0{\text{e}}^{-8.66\times {10}^{-2}\times 32.0}=$ » 1.56 «μg of iodine-131 remain» ✔

Award [2] for correct final answer.