Why is calcium oxide CaO but calcium chloride is CaCl2?

Answer 1

in calcium chloride each calcium atom needs to lose two electrons but each chlorine atom needs to gain only one electron. This means that two chlorine atoms react with every one calcium atom to form calcium chloride. So the formula for calcium chloride is CaCl2.

ca = proton number is 20 so the structure would be 2, 8 ,8 ,2

cl = proton number is 17 so the structure would be 2 , 8,7

To make it stable calcium has to lose 2 electrons and chlorine has to gain an electron. However if you add 2 to 7 in the chlorine it will make 9 so it will still be unstable therefore you need two chlorine atoms to share out the 2 atoms in calcium.

Answer 2

Calcium oxide, CaO, forms a 1:1 ratio between calcium and oxygen atoms, while calcium chloride, CaCl2, forms a 1:2 ratio between calcium and chlorine atoms. This is due to the charges of the ions involved and the need to balance the charges in the compound.