Question

Composition of the nuclei of two atomic species $X$ and $Y$ are given as under
$X$ $Y$
Protons $=$ $6$ $6$
Neutrons$=$ $6$ $8$

Given the mass numbers of $X$ and $Y$. What is the relation between the two species?

Answer 1

Atomic mass=number of protons+number of neutrons

Atomic mass of X = 6+6=12

Atomic mass of Y =6+8=14

Both X and Y have same atomic number but different atomic mass number so they are isotopes.