Question

1. Which of the following pairs of atoms are isotopes?

a) K-39 and K-40
c) C-12 and N-14
b) F-10 and Ne-10
d) H-2 and He-2

Answer 1

Isotopes of an element are atoms of the same element with same number of protons but different number of neutrons. Only choice (b) has 2 atoms of X with 6 protons and 8 and 6 neutrons respectively.

Step-by-step explanation:

b) is the answer