What are the conditions that atoms need to form molecules

Electrons group themselves in pairs in their energy levels. To calculate the number of electrons allowed in any energy level, find the square of the number representing the energy level and multiply it by two. Using this formula, atoms can have two electrons in their first energy level, eight in the second, and eighteen in their third. The quantity of electrons at each level grows as the number of the energy level increases.

14,16 18 reacts with group

the answer is c i believe