Question

What is the electron configuration of an element with atomic number 20? 1s2 2s2 2p6 3s2 3p5 1s2 2s2 2p6 3s2 3p6 1s2 2s2 2p6 3s2 1s2 2s2 2p6 3s2 3p6 4s2 1s2 2s2 2p6 NextReset

Answer 1

Answer: $1s^22s^22p^63s^23p^64s^2$

Explanation:

Electronic configuration represents the total number of electrons that a neutral element contains. We add all the superscripts to know the number of electrons in an atom.

The electrons are filled according to Afbau's rule in order of increasing energies.

The electronic configuration for element with atomic number 20 is Calcium and will have 20 electrons and is written as:

$1s^22s^22p^63s^23p^64s^2$

Answer 2

Electron configuration Should add up to 20 so the answer should be:2,8,8,2