What is calcium-42 electron configuration?

Answer 1

The element calcium, or Ca, is located in group 2, period 4 of the Periodic Table. Therefore, its electron configuration is 1s2 2s2 2p6 3s2 3p6 4s2. This can also be written as [Ar] 4s2, because the beginning of that electron configuration is the same as argon's. The 42 you mentioned in your question is referring to a specific isotope of calcium and has nothing to with the electron configuration.

Answer 2

The electron configuration of calcium-42 is 1s2 2s2 2p6 3s2 3p6 4s1. This means that calcium-42 has 20 electrons distributed across different energy levels and orbitals according to the Aufbau principle.