Question

When calcium (ca) bonds with oxygen, it gives up two electrons. what is the charge of the ca ion in this compound?

Answer 1

Explanation:

Atomic number of calcium is 20 and its electronic distribution is 2, 8, 8, 2. Hence, to attain stability it will readily lose its valence electrons.

Hence, neutral Ca atom will change into $Ca^{2+}$ ion.

Whereas atomic number of oxygen is 8 and its electronic distribution is 2, 6. Hence, to attain stability it will needs to gain two electrons.

Hence, neutral O atom will change into $O^{2-}$ ion.

Therefore, when both calcium and oxygen atoms will chemically combine with each other then according to cross multiplication same charges will be cancelled out resulting in the formation of calcium oxide (CaO) compound.

Thus, we can conclude that charge on calcium in this compound is +2.

Answer 2

1 electron=1 negative charge
lose 2 electrons= lose 2 negative charges

0-(-2)=+2

Ca2+