Bonding 161- B––The Lewis (electron-dot) structure has five
bonding pairs around the central Sb and no lone
pairs. VSEPR predicts this number of pairs to
give a trigonal bipyramidal structure. - B––All the bonds except in CO are single bonds.
The CO bond is a triple bond. Triple bonds are
shorter than double bonds, which are shorter
than single bonds. Drawing Lewis structures
might help you answer this question. - A––Answers B–E contain molecules or ions with
double or triple bonds. Double and triple bonds
contain πbonds. Water has only single (σ) bonds.
If any are not obvious, draw a Lewis structure. - A––The VSEPR model predicts all the other
molecules to be nonpolar. - C––All the other answers involve species contain-
ing only single bonds. Substances without double
or triple bonds seldom need resonance structures. - C––Resonance causes bonds to have the same
average length. - E––Many organic molecules are nonpolar.
Nonpolar substances are held together by weak
London dispersion forces. - D––Lewis structures are required. You do not
need to draw all of them. A and B have one
unshared pair, while C and E have no unshared
pairs. D has two unshared pairs of electrons. - E––Tetrahedral molecules are normally sp^3
hybridized. - D––SiCl 4 , is tetrahedral. BrF 4 −is square planar.
C 2 H 2 is linear. TeF 6 is octahedral. NO 3 −is trigo-
nal planar. If you are uncertain about any of
these, Lewis structures and VSEPR are needed. - A––Only A and E are ionic. The chloride ion has
no internal bonds, so σand πbonds are not
possible.
12–14––Sketch a molecular orbital energy-level dia-
gram. Use the same diagram to save time, unless
it becomes too messy.- D
- A
- D
- A––This hybridization requires a geometrical
shape with three corners. - B––One or more Lewis structures may help you.
I and III are tetrahedral, and II is an irregular
tetrahedron (see-saw). - B––A has 0. B has 2. C and D have 0. E has 1. You
may need to draw one or more Lewis structures. - B––All the molecules are polar except B.
- E––The structure is:
All the carbon atoms have one double and two
single bonds. This combination is sp^2.- E—Drawing one or more Lewis structures may
help you. Only C and E are polar. Only the
ammonia has hydrogen bonding, which is very,
very polar. - E—C is metallic bonding. All the others involve
covalently bonded molecules.
H—C=C—C=C—H
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Answers and Explanations