Question

1. sulfur trioxide is known to be planar with all the oxygen atoms equidistant from the central sulfur atom. on the basis of these facts, which of the following statements are correct? 1. it can be represented by three equivalent resonance structures. 2. the sulfur atom is sp² hybridized. 3. the molecule is nonpolar. a) 1 only b) 2 only c) 3 only d) 1 and 2 e) 1, 2, and 3 29. for which of the following compounds is it possible for cis and trans isomers to exist? a) 1 only b) 2 only c) 3 only d) 1 and 2 e) 1, 2, and 3 30. which of the underlined atoms (c₁, c₂, n, and o) are sp² hybridized? a) c₁ and c₂ b) c₁, n, and o c) n and o d) o and c₂ e) o only 31. all of the following statements concerning molecular orbital (mo) theory are correct except a) the pauli exclusion principle is obeyed. b) hund’s rule is obeyed. c) the combination of two atomic orbitals creates one molecular orbital. d) a bonding molecular orbital is lower in energy than its parent atomic orbitals. e) electrons are assigned to orbitals of successively higher energy.

Explanation:

28.

Step1: Analyze resonance structures

Sulfur trioxide ($SO_3$) has three equivalent resonance - structures due to the delocalization of $\pi$ - electrons. The sulfur - oxygen bonds are of equal length because of resonance.

Step2: Determine hybridization

The sulfur atom in $SO_3$ is $sp^{2}$ hybridized. It forms three $\sigma$ - bonds with oxygen atoms and has a trigonal - planar geometry.

Step3: Check polarity

The molecule is non - polar. The trigonal - planar geometry and the equal pull of the oxygen atoms on the sulfur atom result in a symmetric distribution of charge, making the molecule non - polar.

Step1: Recall conditions for cis - trans isomerism

Cis - trans isomerism occurs in alkenes where each carbon of the double bond is attached to two different groups.

Step2: Examine each compound

• Compound (1): The first carbon of the double bond has two hydrogen atoms, so it cannot exhibit cis - trans isomerism.
• Compound (2): Each carbon of the double bond is attached to two different groups (a hydrogen and a methyl group), so it can exhibit cis - trans isomerism.
• Compound (3): Each carbon of the double bond is attached to two different groups (a hydrogen and a methyl group), so it can exhibit cis - trans isomerism.

Step1: Analyze $C_1$

The $C_1$ atom has a double bond with oxygen and two single bonds with other atoms. It is $sp^{2}$ hybridized.

Step2: Analyze $C_2$

The $C_2$ atom is part of a double - bond in a ring structure. It is $sp^{2}$ hybridized.

Step3: Analyze $N$

The nitrogen atom has a lone pair and is single - bonded to carbon and hydrogen atoms. It is $sp^{3}$ hybridized.

Step4: Analyze $O$

The oxygen atom has two lone pairs and is single - bonded to carbon. It is $sp^{3}$ hybridized.

Answer:

e) 1, 2, and 3

29.