Nucleophile in a SN2 reaction In a $\mathrm{S_N2}$ reaction, a good nucleophile is considered to be willing to donate electrons. So how do we generalize this fact across the periodic table? Does that mean the more electronegative an atom is, the better the nucleophile?
As electronegativity increases the holding capacity of electron by the atom increases. So it is less likely to donate electrons. So we can generalise that access a period in periodic table nucleophilicity decreases.