What is the chemical formula for calcium oxide?

1 Answer
Meave60
Nov 6, 2014

The formula for calcium oxide is CaO.

Explanation:

Calcium oxide is an ionic compound composed of the metal calcium and nonmetal oxygen.

Calcium is an alkali earth metal (group 2/IIA). The atoms of the alkali earth metals have two valence electrons, which they lose when forming ions. Therefore, calcium cations have a charge of #2^+#.

Oxygen is in group 16/VIA and the atoms of all elements in this group have six valence electrons, and need two more to have an octet and become stable. Therefore, oxide anions have a charge of #2^(-)#.

The overall charge of an ionic compound is zero. Since the charges of the calcium and oxide ions are equal but opposite, the calcium and oxide ions form a #1:1# ratio #(2^+ + 2^(-)=0)#, and the chemical formula is #"CaO"#.

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

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