Question

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?

Answer 1

We can find mass number using the following formula:​

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

Given,​

		X	Y
Proton	=	6	6
Neutrons	=	6	8

The atom X: ​

Mass number = 6 + 6 = 12​

Atomic number = 6.​

The atom Y:​

Mass number = 6 + 8 = 14​

Atomic number = 6​

Here, the atomic number is same for both, and the mass number is different. Therefore, X and Y are isotopes.