Key terms: reset functional groups create sites in molecules. the polar part of a molecule that can hydrogen bond to water is said be . pi (π) bonds create sites and will react with electron-deficient species. a electronegative heteroatom like nitrogen, oxygen, or a halogen makes a carbon atom . the nonpolar part of a molecule that is not attracted to water is said to be . a lone pair on a heteroatom makes it basic and .