How does calcium obey the octet rule when reacting to form compounds?

1 Answer
Stefan V.
Feb 1, 2016

It loses two electrons from its outermost shell.

Explanation:

Calcium, "Ca", is located in group 2 of the periodic table, which means that is has two electrons on its outermost shell.

In order to have a complete octet, calcium must lose these two outermost electrons, also called valence electrons.

Calcium will react with nonmetals to form ionic compounds.

The electron configuration for a neutral calcium atom looks like this

"Ca: " 1s^2 2s^2 2p^6 3s^2 3p^6 color(red)(4)s^2

After the two outermost electrons are lost, which in a neutral atom occupy the fourth energy level, the calcium cation, "Ca"^(2+), is formed. Its electron configuration looks like this

"Ca"^(2+): 1s^2 2s^2 2p^6 color(red)(3)s^2 color(red)(3)p^6

By losing its valence electrons, calcium completes its octet. The outermost shell, which is now the third energy level, holds a total of eight electrons -> a complete octet

http://spmchemistry.onlinetuition.com.my/2013/10/ionic-bonding.html

For example, calcium will react with oxygen to form calcium oxide, "CaO". Calcium will donate its two valence electrons to oxygen, forming the "Ca"^(2+) cation.

Oxygen will pick up these two electrons, forming the "O"^(2-) anion. The resulting compound, "CaO", will thus be electrically neutral.

Related questions
See all questions in Octet Rule
Impact of this question
34512 views around the world
You can reuse this answer
Creative Commons License