Question

A radioactive source emits three types of radiation.
a) When the alpha particle becomes neutral, it is found to be the atom of a rare gas. Name this rare gas and draw a model of its neutral atom.
b) From which part of the atom do these radiations come?

Answer 1

Radioactivity is a nuclear phenomenon of spontaneous emission of $\alpha \text{(Alpha),}\beta \text{(Beta) and}\gamma \text{(Gama)}$ radiations from the nucleus of atoms during their decay.
(a) Alpha $\left(\alpha \right)$ radiation is composed of two protons and two neutrons, same as doubly ionized $He$ atom, $H{e}^{2+}$.When the alpha particle becomes neutral, it represent the atom of Helium gas like as follows :
$H{e}^{+2}+2_{-1}{e}^0\to He$
(b) These radiations $(\alpha ,\beta ,\gamma \text{particle})$ originate from the nucleus of the atom.