* Calcium (Ca) has 2 valence electrons and wants to lose them to achieve a stable octet (8 electrons in its outer shell).
* Sulfur (S) has 6 valence electrons and wants to gain 2 electrons to achieve a stable octet.
To balance this out, you need one calcium atom for every one sulfur atom.
Here's why:
* The calcium atom will lose its 2 valence electrons, becoming a Ca²⁺ ion (with a +2 charge).
* The sulfur atom will gain those 2 electrons, becoming an S²⁻ ion (with a -2 charge).
The opposite charges attract, forming a strong ionic bond between the Ca²⁺ and S²⁻ ions. This results in the compound Calcium Sulfide (CaS).
