⇒Nucleophile is a substance that seeks a positive center. Electrophiles seek negative centers which have extra electrons.
⇒A nucleophile can be any negative ion or any neutral molecule that has at least one unshared electron pair. Carbocations and other, completely or partially, positive charged species can act as electrophiles.
⇒Nucleophile is a Lewis base, and an electrophile is a Lewis acid.
⇒In a reaction mechanism, arrows are always drawn to show the electron flow from a nucleophile to the electrophile.