Define electrophile and nucleophile

Electrophile is an ion or molecule that is electron deficient and can accept electrons. Electrophiles are often reducing agents and Lewis acids. They are either positive ions (e.g. NO2+) or molecules that have a positive charge on a particular atom (e.g. SO3, which has an electron deficient sulphur atom). In organic reactions they tend to attack negatively charged parts of a molecule. Types of electrophiles: Lewis acids, cations and electron deficient sites in organic compounds

Nucleophile is an ion or molecule that can donate electrons. Nucleophiles are often oxidizing agents and Lewis bases. They are either negative ions (e.g. Cl) or molecules that have electron pairs (e.g. NH3). In organic reactions they tend to attack positively charged parts of a molecule. Types of nucleophiles: Lewis bases, anions and electron rich sites in organic compounds.