Question

nucleophiles and electrophiles

Answer 1

nucleophiles - it is a chemical specie that donates an electron pair to an electrophile to form a chemical bond in relation to a reaction.
  
electrophile - it is a reagent attracted to electrons.

Answer 2

Nucleophiles is of two types neutral nucleophile and negative nucleophile.
it is electron rich species and has more electron density . it involves in the nucleophilic substitution reaction.
electrophiles is electron deficient species and has less electron density. it involves electrophilic substitution reaction.