Composition of the nuclei of two atomic species X and Y are given as under
 
 
X
Y
Protons \(6\) \(6\)
Neutrons \(6\) \(8\)
  
Give the mass number of X and Y and state the relation between the two species?
Mass number \(=\) Number of protons \(+\) Number of
Mass number of X \(=\) 
Mass number of Y \(=\)
Both X and Y have the same atomic number (\(6\)) but different neutrons, so they are of same element.