A helium balloon initially at room temperature is dunked into a bucket of liquid
nitrogen (T = 77 K). Which of the following will occur?

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.

the correct answer is:

a. formation of precipitation