In dinitrogen gas, ##N_2##, there are 5 associated with each nitrogen atom.
##N##, ##Z=7##, and thus 7 electrons associated with the neutral atom.
Two of these electrons are inner core, and do not participate in . The remaining 5 electrons are the , and 6 of these bind between the nitrogen nuclei together in forming chemical bonds.
Given that a single bond is composed of 2 electrons, the ##:N-=N:## representation clearly shows the disposition of the 10 remaining electrons.
If we look at nitrogen , the simplest one is ammonia, ##:NH_3##, which is (i) hard to make; and (ii) absolutely vital to agriculture. Nitrogen here is considered to be neutral because it has 2 electrons from its lone pair, and a half share of the 6 electrons that make up the ##3xxN-H## bonds. ##5+2″ inner shell electrons”## balance the charge of the 7 protons in the nitrogen nucleus.
But nitrogen is a base, and has a formal lone pair, which is conceived to form a donative bond to ##H^+## in an acid base reaction:
##NH_3(aq) + H_2O rightleftharpoons NH_4^+ + HO^-##
The nitrogen centre is now quaternized, and is depicted with a formal positive charge (6 electrons rather than the 7 required for neutrality).
