Chemical Bonding and Molecular Structure Chapter-Wise Test 1

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which molecule contains a triple bond and has a bond length shorter than that of \( \ce{O2} \) (121 pm)?

\( \ce{N2} \) has a triple bond with a bond length of ~110 pm, shorter than \( \ce{O2} \)’s double bond (121 pm) due to higher bond order (3 vs. 2).

\( \ce{C2H4} \)
\( \ce{N2} \)
\( \ce{CO2} \)
\( \ce{H2O} \)
2

Which molecule has a bond angle closest to 109.5°?

In \( \ce{SiCl4} \), silicon is \( sp^3 \) hybridized with no lone pairs, resulting in a tetrahedral shape with a bond angle of 109.5°.

\( \ce{NH3} \)
\( \ce{H2O} \)
\( \ce{SiCl4} \)
\( \ce{PH3} \)
3

The number of lone pairs on xenon in \( \ce{XeF6} \) is:

In \( \ce{XeF6} \), xenon has 8 valence electrons, forms 6 bonds (12 electrons used), leaving 2 electrons as 1 lone pair in a \( sp^3d^3 \) hybridized state.

2
3
1
0
3

Which molecule has a coordinate bond where nitrogen donates a lone pair to a metal ion?

In \( \ce{[Cu(NH3)4]^2+} \), each \( \ce{NH3} \) donates a lone pair from nitrogen to \( \ce{Cu^2+} \), forming coordinate bonds.

\( \ce{[Cu(NH3)4]^2+} \)
\( \ce{CH4} \)
\( \ce{H2O} \)
\( \ce{N2} \)
1

Which molecule has all its electrons paired, making it diamagnetic?

For \( \ce{F2} \): \( (\sigma 1s)^2 (\sigma^* 1s)^2 (\sigma 2s)^2 (\sigma^* 2s)^2 (\sigma 2p_z)^2 (\pi 2p_x)^2 (\pi 2p_y)^2 (\pi^* 2p_x)^2 (\pi^* 2p_y)^2 \). All electrons are paired, so it’s diamagnetic.

\( \ce{F2} \)
\( \ce{O2} \)
\( \ce{B2} \)
\( \ce{NO} \)
1

The shape of \( \ce{TeF6} \) molecule is:

In \( \ce{TeF6} \), tellurium is \( sp^3d^2 \) hybridized with 6 bonding pairs and no lone pairs, resulting in an octahedral shape.

Square pyramidal
Trigonal bipyramidal
Octahedral
Distorted octahedral
3

What is the total number of valence electrons in the \( \ce{CO} \) molecule?

Carbon has 4 valence electrons, and oxygen has 6. Total = 4 + 6 = 10 valence electrons in \( \ce{CO} \).

8
12
10
14
3

Which molecule exhibits hydrogen bonding as its strongest intermolecular force?

In \( \ce{NH3} \), hydrogen bonding occurs between the hydrogen of one molecule and the nitrogen lone pair of another, stronger than van der Waals forces in others.

\( \ce{CH4} \)
\( \ce{NH3} \)
\( \ce{Cl2} \)
\( \ce{CO2} \)
2

Which species is paramagnetic and has a bond order of 2?

For \( \ce{O2} \): \( (\sigma 1s)^2 (\sigma^* 1s)^2 (\sigma 2s)^2 (\sigma^* 2s)^2 (\sigma 2p_z)^2 (\pi 2p_x)^2 (\pi 2p_y)^2 (\pi^* 2p_x)^1 (\pi^* 2p_y)^1 \). Bonding = 10, antibonding = 6. Bond order = \( \frac{10 - 6}{2} = 2 \), with 2 unpaired electrons (paramagnetic).

\( \ce{N2} \)
\( \ce{F2} \)
\( \ce{O2} \)
\( \ce{C2} \)
3

The shape of \( \ce{BrF3} \) molecule is:

In \( \ce{BrF3} \), bromine is \( sp^3d \) hybridized with 5 electron pairs (3 bonding, 2 lone), resulting in a T-shaped molecular geometry.

Trigonal planar
See-saw
Square pyramidal
T-shaped
4

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