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

Apr 18, 2016

#### Answer:

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

#### Explanation:

The element with an atomic number of $20$ is Calcium $C a$.

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: