What happens when a sodium atom loses an electron in its outer energy shell?

Answer : When a sodium atom loses an electrons in its outer energy then it will form a cation.

Explanation :

The sodium is metal that belongs to group 1 with atomic number 11.

The electronic configuration of sodium is,

As we know that sodium atom loses an electron easily to acquire the stability.

The electronic configuration of sodium ion is,

According to the question, when a sodium atom loses an electron in its outer energy shell or valence shell then it becomes a cation which is a positively charged ion. That means sodium cation having charge (+1).

Hence, when a sodium atom loses an electrons in its outer energy then it will form a cation.