Composition of the nuclei of two atomic species X and Y are given as under
`{:(,=,X,Y),("Proton",=,6,6),("Neutrons",=,6,8):}`
Give the mass numbers of X and Y. What is the relation between the two species ?

Explanation

Mass number = Number of protons + Number of neutrons
Mass number of X = 6 + 6 = 12
Mass number of Y = 6 + 8 = 14
Atomic number = Number of protons
Atomic number of X = 6
Atomic number of Y = 6
Since X and Y have the same atomic number but different mass number they are isotopes .