a nucleophile is an electron pair donor and have at least 1 lone pair of electrons. they have a partial or full negative charge and are attracted to the slightly positive electron deffiecient atoms. Examples of these are:OH- , CN- , NH3 and H2O. Remember to always drAw them there lone pair!
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The Mechanism
the nucleophile uses its lone pair to provide the electrons for a new bond.
the halogen is displaced. carbon can only have 8 electrons in its outer shell.
the nucleophile replaces the halogen.
the mechanism is there for known as:
NUCLEOPHILLIC SUBSTITUTION
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the steps in the mechanism
nucleophiles have lone pair of electrons
the carbon-hydrogen bond is polar
a curly arrow is drawn from the lone pair to the slightly positive carbon atom
a curly arrow is used to shown the movement of a pair of electrons
carbon is restricted to only 8 electrons in its outer shell, so a bond must be broken.
the polar carbon-hydrogen bond breaks.
the second curly arrow shows the shared pair moving onto the halogen
the halogen now has its own electron pair back plus the pair from the carbon atom
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