Chemical bonding

Nitrogen in ammonia has three bonding pairs and one lone pair, resulting in a tetrahedral electron domain geometry but a trigonal pyramidal molecular shape due to lone-pair repulsion. Option B is incorrect because tetrahedral describes the arrangement of all electron domains, whereas molecular geometry only describes the positions of the atoms.

Carbon in methane forms four single sigma bonds with hydrogen atoms and has zero lone pairs, giving it a steric number of four which corresponds to sp3 hybridisation. Option B is incorrect because sp2 hybridisation requires three steric domains, which is typically found in molecules containing a double bond, like ethene.

Carbon in methane forms four single sigma bonds with hydrogen atoms and has zero lone pairs, giving it a steric number of four which corresponds to sp3 hybridisation. A diagram for this topic isn't available yet — the worked example below walks the same reasoning step by step.

• !Option B is incorrect because sp2 hybridisation requires three steric domains, which is typically found in molecules containing a double bond, like ethene.
• !Option B is incorrect because tetrahedral describes the arrangement of all electron domains, whereas molecular geometry only describes the positions of the atoms.
• !Option B (109.5 degrees) is incorrect because that tetrahedral angle corresponds to sp3 hybridization.
• !Option B is incorrect because a bond order of 2 corresponds to a double bond, as seen in oxygen gas which has more antibonding electrons.

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