Isotopes:
Isotopes are atoms of the same element that have the same number of protons (hence the same atomic number) but differ in the number of neutrons. The electronic configuration of isotopes remains the same since they share the same number of protons and electrons.

For instance, considering hydrogen isotopes:
– Hydrogen-1 (^1H): Electronic configuration – 1s¹
– Deuterium (^2H): Electronic configuration – 1s¹

**Isobars:**
Isobars are atoms of different elements that have the same mass number (total number of protons and neutrons) but different atomic numbers. As a result, they have different electronic configurations.

For example, comparing carbon-14 (^14C) and nitrogen-14 (^14N):
– Carbon-14 (^14C): Electronic configuration – 1s² 2s² 2p²
– Nitrogen-14 (^14N): Electronic configuration – 1s² 2s² 2p³