# Question #56d50

Feb 6, 2016

A neutral oxygen atom has 8 protons, 8 fundamental POSITIVE nuclear charges. To balance this charge there must be 8 corresponding NEGATIVE particles, or 8 electrons. When we write our formula of water, ${H}_{2} O$, there is NO formal charge. For $H$, $Z = 1$; hydrogen has a share in ONE of the 2 electrons conceived to participate in the $O - H$ bond.
By this criterion, oxygen gets 2 electrons, and there are 2 oxygen-based lone pairs ($2$ $\times$ $2$ electrons), which are "owned" by oxygen. So oxygen has 6 electrons so far (i.e. valence electrons) + 2 inner core electrons. Thus oxygen is NEUTRAL. You can usually always easily assign the electrostatic charge by these methods, but this is a first year problem not an A level type of question.
Can you tell me the charge distribution in nitrate anion, $N {O}_{3}^{-}$; there are 25 valence electrons to distribute, and BOTH nitrogen and $2$ oxygens have formal charges.