Answer
See the answer below.
Work Step by Step
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.
