Question

chemistry 4 ch class 9​

Answer 1

Atomic mass of element is equal to the sum of protons and neutrons in the element.

Mass number of X - 6 + 6 = 12u

Mass number of Y - 6 + 8 = 14u

We know that isotopes of elements have the same atomic number but different atomic masses.

The atomic number of an element is the number of protons in the element.

So both X and Y have atomic number (number of protons) 6 , hence X and Y are isotopes.

Answer 2

The total mass of x =sum of proton and nuetron
6+6=12u
y =6+8=14u

They are isotopes as all chemical properties and atomic number same but mass number is different