## Chemistry and Chemical Reactivity (9th Edition)

a) Amide ion makes two bonds and has two lone pairs: tetrahedral electron-pair geometry and bent molecular geometry. Sulfur trioxide makes two single and a double bond, with no lone pairs: trigonal planar electron-pair and molecular geometries. b,c) $\begin{smallmatrix} &&&&O\\ &&&&|\\ H&-&N&-&S&-&O\\ &&|&&|\\ &&H&&O \end{smallmatrix}$ All bond angles are approximately 109° because all atoms involved are $sp^3$ hybridized. Nitrogen maintains its hybridization, while sulfur goes from $sp^2$ to $sp^3$. d) Sulfur is the lone pair acceptor, because it doesn't have any to donate and it has a positive partial charge, whilst nitrogen has a negative one. The potential surface confirms this prediction.