Nuclear and particle physics

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Question 47

Medium

An isotope of actinium-228 ( $89228Ac^{228}_{89}\text{Ac}$ ) first decays into an isotope of thorium-228 ( $90228Th^{228}_{90}\text{Th}$ ) and this thorium isotope then decays into the isotope of radium-224 ( $88224Ra^{224}_{88}\text{Ra}$ ).

The figure below shows two arrows on a neutron number $N$ against proton number $Z$ chart to illustrate these two decays.

Segrè chart showing Neutron number N against Proton number Z

Complete the nuclear decay equations for:

(i) the actinium isotope: $……^{228}_{89}\text{Ac} \rightarrow \ \dots\dots\ \text{Th} + \ ^{0}_{-1}\text{e} + \ \dots\dots$

(ii) the thorium isotope: $……^{228}_{90}\text{Th} \rightarrow \ ^{224}_{88}\text{Ra} + \ \dots\dots$

[3]

A pure sample of actinium-228 is being produced in a research laboratory.

The half-life of actinium-228 is $hours6.15\text{ hours}$ .

(i) Briefly describe and explain an experiment that can be carried out to confirm that alpha radiation is emitted from the thorium nuclei.

(ii) The activity of the sample of $89228Ac^{228}_{89}\text{Ac}$ after $hours12.0\text{ hours}$ is $kBq15.0\text{ kBq}$ .

Calculate the initial number of actinium-228 nuclei in this sample.

[6]

Nuclear and particle physics

Question 47

Nuclear and particle physics Questions

Nuclear and particle physics

Question 47

Nuclear and particle physics Questions