Nuclear species or nuclides are shown by the notation X
ZA
 where X is
the chemical symbol of the species For example, the nucleus of gold is
denoted by 197
79 Au It contains 197 nucleons, of which 79 are protons
and the rest118 are neutrons Rationalised 2023-24
309
Nuclei
The composition of isotopes of an element can now be readily
explained