Structure of the Atom — Question 2

(a) Isotopes — Carbon has two isotopes i.e., ₆C¹² and ₆C¹⁴. They have same electronic configuration as they have same atomic numbers = 6. Hence, their electronic configuration is 2, 4.

(b) Isobars — Calcium [₂₀Ca⁴⁰] atomic number 20 and argon [₁₈Ar⁴⁰] atomic number 18 are isobars as both have same mass number i.e., 40 and different atomic numbers.

Electronic configuration of ₂₀Ca⁴⁰ is 2, 8, 8, 2.

Electronic configuration of ₁₈Ar⁴⁰ is 2, 8, 8.