Decoding the language

[kenhung123]

I am reading the text book and they are talking about reactants that have "non bonding electron pair e.g. OH-" are attractive to the carbon-halogen bonds in haloalkanes. What does non bonding electron pair mean?

[luken93]

Well for each element, the way we look at the number of valence electrons is by the number of pairs.
Lets look at oxygen  for example.
It has 6 valence electrons
When it bonds with 2x H atoms to form H2O, the single valence electron from the hydrogens bond with two of the oxygen's valence electrons. Hence there will be two bonding pairs, and 2 non bonding pairs, because oxygen only uses two of its valence electrons to bond with hydrogen. If you need more info, try to have a look at Lewis Diagrams, that will make it easier