To form a hydrogen bond, what must the non-hydrogen atom ( n , o , or f ) involved in the bond possess?

Explanation:

As atomic number of hydrogen is 1. So, it needs to gain one electron from a donor atom in order to become stable in nature.

Therefore, when a hydrogen bond is formed with a non-hydrogen atom then there must be presence of a non-bonding electron.

For example, atomic number of nitrogen atom is 7 and its electronic distribution is 2, 5.

Here, three electrons are needed by a nitrogen atom. And, when three nitrogen atoms get attached to a nitrogen atom then a compound is formed.

Thus, we can conclude that to form a hydrogen bond, the non-hydrogen atom ( N , O , or F ) involved in the bond must possess a non-bonding electron pair.

the answer is na (sodium)