Phosphorus-32 is a radioactive isotope. It can be used to prove that plants absorb phosphorus from the soil around them.

a. i. The stable isotope of phosphorus has a mass number of 31. State the structural difference between atoms of phosphorus-31 and phosphorus-32.

ii. Explain why both isotopes of phosphorus have identical chemical properties.

b. Phosphorus-32 is a beta-emitter with a half-life of 14 days.

i. What is a beta particle?

ii. The proton number of phosphorus-32 atom is 15. State the new values of the proton number and mass number of the atom just after it has emitted a beta particle.

iii. Explain what is meant by the term half-life.

c. A solution of the isotope is watered onto the soil around the plant. Each day for the next it week, a leaf is removed from the plan and tested for radioactivity.

i. State three safety precautions which should be adopted when doing experiments with phosphorus-32.

ii. Describe two methods which could be used to measure the activity of a leaf.