What is the valence electron configuration for calcium?

1 Answer

$begingroup$ What you provided is the ground-state configuration for calcium. In theory every atom 'has' d-electrons, just not in the ground state. When excited (which is usually VERY rare), electrons can bump up to higher energy levels like p,d,f,etc. $endgroup$ – khaverim Mar 5 '16 at 3:47. Calcium has 20 electrons and oxygen has 8 electrons, so the TOTAL number of electrons in CaO is 28. If you mean how many valence electrons are used, then calcium uses 2 valence electrons,. Calcium has 20 electrons and m shell is a 3rd energy level. Its electronic configuration is 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 instead of 1s 2 2s 2 2p 6 3s 2 3p 6 3d 1 4s 1. This is because of Afbau’s principle which states that electrons fill orbitals starting at the lowest available (possible) energy levels before filling higher levels (e.g. 1s before 2s and 4s before 3d).

Calcium can be found in the 4th energy level (row) of the periodic table, and in the 2nd group (column). The first two groups (columns) of the periodic table represent the 's' orbital group. This means that the electron configuration for calcium must end with #4s^2#. The 4th energy level (row), 's' orbital block, 2nd group (column).

The total electron configuration is:

#1s^2 2s^2 2p^6 3s^2 3p^6 4s^2# or #[Kr] 4s^2#

The valence electrons are found in the highest energy level of the electron configuration in the 's' and 'p' orbitals.

In the case of calcium this is #4s^2#. This gives calcium an 's' orbital with a pair of electrons in its valence shell.

I hope this was helpful.
SMARTERTEACHER

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