Which of the following statements about hybrid orbitals is or are true? (i) After an atom undergoes sp hybridization, there is one unhybridized p orbital on the atom, (ii) Under sp2 hybridization, the large lobes point to the vertices of an equilateral triangle, and (iii) The angle between the large lobes of sp3 hybrids is 109.5°.
For one of the resonance forms of ozone, O3, which of the orbitals are used to make bonds and which are used to hold nonbonding pairs of electrons?

Key Concepts
Resonance Structures
Molecular Orbitals
Lone Pairs and Bonding Pairs
Sodium azide is a shock-sensitive compound that releases N2 upon physical impact. The compound is used in automobile airbags. The azide ion is N3-. (a) Draw the Lewis structure of the azide ion that minimizes formal charge (it does not form a triangle). Is it linear or bent?
Sodium azide is a shock-sensitive compound that releases N2 upon physical impact. The compound is used in automobile airbags. The azide ion is N3-. (b) State the hybridization of the central N atom in the azide ion.
In ozone, O3, the two oxygen atoms on the ends of the molecule are equivalent to one another. (d) How many electrons are delocalized in the p system of ozone?
Butadiene, C4H6, is a planar molecule that has the following carbon–carbon bond lengths:
(a) Predict the bond angles around each of the carbon atoms and sketch the molecule.
Butadiene, C4H6, is a planar molecule that has the following carbon–carbon bond lengths:
(b) From left to right, what is the hybridization of each carbon atom in butadiene?