Part 1: Answer All Questions. (1 mark each)
1. The formal charges on the three O -atoms of ozone for one of its resonance structures, \( \mathrm{O}=0 \cdot \mathrm{O} \) : (in order) are
(a) \( 0,-1,+1 \)
(b) \( +1,0,-1 \)
(c) \( 0,+1,-1 \)
(d) \( -1,+2,-1 \)
2. Which is the correct basic shape and hybridization of XeF, that satisfies both VSEPR and valance bond theories?
(a) Octahedral,
(b) Square planar,
(c) Trigonal bipyramidal,
(d) Square pyramidal,
\( s p^{3} d^{2} \)
\( s p^{3} d^{2} \)
\( s p^{3} d \)
\( s p^{3} \mathrm{~d} \)
3. Among the compounds, \( \left[\mathrm{NO}_{2}\right]^{\circ}, \mathrm{CO}_{2},\left[\mathrm{NO}_{2}\right]^{\circ},\left[\mathrm{N}_{3}\right] \), one is not isoelectronic with the rest of them: Which is the odd one out?
(a) \( \left[\mathrm{NO}_{2}\right]^{+} \)
(b) \( \mathrm{CO}_{2} \)
(c) \( \left[\mathrm{NO}_{3}\right]^{-} \)
(d) \( \left[\mathrm{N}_{3}\right]^{-} \)
\( 2+5+2 \times 8-16=22 \quad 3 \times 7+1 \)
\[
\begin{array}{l}
=6+2 \times 8=72=72 \\
\mathrm{HNO}_{2} ?
\end{array}
\]
A. Which of the following Lewis structures is correct for \( \mathrm{HNO}_{2} \) ?
(a)
(b)
(c)
(d)
8. According to molecular orbital (MO) theory, the structure of \( \mathrm{SF}_{5} \) is stable due to
(a) Filled bonding MOs and empty non-bonding and anti-bonding MOs (b) Filled bonding and nonbonding MOs and empty anti-bonding MOs (c) Filled bonding MOs, partially filled non-bonding MOs and empty anti-bonding MOs (d) Filled bonding and non-bonding MOs and partially-filled antibonding MOs