Question

Which statements correctly describe the decay rates of radioactive isotopes?

a} It takes two half-lives for a sample to fully decay.

b} The exact time when an individual atom will decay can be accurately predicted.

c} After each half-life, the amount of radioactive material is reduced by half.

d) All radioactive isotopes have the same half-life.

e} The decay of individual atoms in a sample of radioactive material is random.

Answer 1

For plato, the answer is C: after each half tile, the amount of radioactive material is reduced by half

Answer 2

Answer: b} The exact time when an individual atom will decay can be accurately predicted.

c} After each half-life, the amount of radioactive material is reduced by half.

Step-by-step explanation:

All radioactive decay follows first order kinetics.

Rate law expression for first order kinetics is given by:

`t=(2.303)/(k)\log(a)/(a-x)`

where,

k = rate constant

t = time taken for decay process

a = initial amount of the reactant

a - x = amount left after decay process

Expression for calculating half life, which is the time taken by the half of the reactants to decompose is:

`t_(1/2)=(0.693)/(k)`