Question

What is the electron configuration of an element with atomic number 20?

Answer 1

`""_20Ca:1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)4s^(2)`

Explanation:

The element with an atomic number of `20` is Calcium `Ca`.

The electron configuration is:
`""_20Ca:1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)4s^(2)`

The electron configuration is found using the Aufbau principle: