MCAT Organic Chemistry Review 2018-2019

Figure 4.2. Examples    of  Nucleophiles

KEY CONCEPT

Nucleophiles    tend    to  have    lone    pairs   or  π   bonds   that    can be  used    to  form    covalent    bonds   to

electrophiles.  On  Test    Day,    look    for carbon, hydrogen,   oxygen, or  nitrogen    (CHON)  with    a

minus   sign    or  lone    pair    to  identify    most    nucleophiles.

As long as the nucleophilic atom is the same, the more basic the nucleophile, the more reactive it is.
This also holds when comparing atoms in the same row of the periodic table, but not when
proceeding down a column in the periodic table. Nucleophilicity is determined by four major
factors:

Charge: Nucleophilicity increases   with    increasing  electron    density (more   negative    charge)

Electronegativity:  Nucleophilicity decreases   as  electronegativity   increases   because these   atoms

are less    likely  to  share   electron    density

Steric  hindrance:  Bulkier molecules   are less    nucleophilic

Solvent:    Protic  solvents    can hinder  nucleophilicity by  protonating the nucleophile or  through

hydrogen    bonding