What happens to the electronegatity when you go from top to bottom on the periodic table?

It decreases

Explanation:

As you go down a group from top to bottom, the electronegativity decreases. Across a period, electronegativity increases from left to right.

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.