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

1 Answer
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: 1s22s22p63s23p64s2

After the two outermost electrons are lost, which in a neutral atom occupy the fourth energy level, the calcium cation, Ca2+, is formed. Its electron configuration looks like this

Ca2+:1s22s22p63s23p6

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 Ca2+ cation.

Oxygen will pick up these two electrons, forming the O2 anion. The resulting compound, CaO, will thus be electrically neutral.