Question

When a boron nucleus is bombarded by a neutron, a α-particle is emitted. Which nucleus will be formed as a result?

Answer 1

It is given that when a boron nucleus $\left({}_5{}^{10}\mathrm{B}\right)$ is bombarded by a neutron, an α-particle is emitted.

Let X nucleus be formed as a result of the bombardment.
According to the charge and mass conservation,

$$\begin{gathered} {}_5{}^{10}B+{}_0{}^{1}n\to X+{}_2{}^{4}He \\ \mathrm{Charge}:50\underline{3}2 \\ \mathrm{Mass}:101\underline{7}4 \end{gathered}$$

The mass number of X should be 7 and its atomic number should be 3.

$\therefore X={}_3{}^{7}Li$