Composition of the nuclei of two atomic species X and Y is given as under:

X Y


Protons = 6 6


Neutrons = 6 8


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

We know that:

Mass number = No. of protons + No. of neutrons


So, Mass number of X = 6 + 6


= 12


Mass number of Y = 6 + 8


= 14


Thus, the mass number of X is 12 and that of Y is 14


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