Question

An element $$_{Z}P^{A}$$ emits one α-particle and then two β-particles consecutively to form an element Q.

1. Show all the transformations by means of equations only.
2. What are P and Q called?

Answer 1

(a)\[ {}_{Z}\mathrm{P}^{A} \longrightarrow {}_{Z - 2}\mathrm{X}^{A - 4} + {}_{2}\mathrm{He}^{4} \]

\[ {}_{Z - 2}\mathrm{X}^{A - 4} \longrightarrow {}_{Z - 1}\mathrm{Y}^{A - 4} + {}_{-1}\mathrm{e}^{0} \]

\[ {}_{Z - 1}\mathrm{Y}^{A - 4} \longrightarrow {}_{Z}\mathrm{Q}^{A - 4} + {}_{-1}\mathrm{e}^{0} \]

(b) P and Q are called isotopes, because they have the same atomic number (Z) but different mass numbers (A and A − 4).