ICSE Class 8 Answered

Sodium chloride

Sodium atom has 1 electron in the valence shell which it donates to the chlorine atom with 7 electrons in the valence shell to attain the stable electronic configuration of the nearest inert gas, i.e. 8 electrons in the valence shell. This is known as the octet rule. This is result into formation of ions ,   Sodium atom who loses its outermost one electron will form cation Na⁺ and chlorine who accept one electron will form negaative charge, Cl^-,  both these ions of sodium and chlorine elements combine to form sodium chloride.

Elements present at left side of periodic table (Sodium) are tend to form cations and elemnts those are present at the right of periodic table (Chlorine) are tend to form anions.