Chemical Bonding and Molecular Structure Chapter-Wise Test 8

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which molecule violates the octet rule due to having more than 8 electrons around the central atom in its Lewis structure?

In \( \ce{BrF5} \), bromine has 5 bonds (10 electrons) and 1 lone pair (2 electrons), totaling 12 electrons, exceeding the octet via d-orbital use.

\( \ce{BrF5} \)
\( \ce{BF3} \)
\( \ce{NH3} \)
\( \ce{CH4} \)
1

Which of the following atoms achieves a stable octet by gaining one electron?

Chlorine (Cl) has 7 valence electrons (\( [\ce{Ne}] 3s^2 3p^5 \)). Gaining one electron forms \( \ce{Cl^-} \) with a noble gas configuration (\( [\ce{Ar}] \)).

Cl
Na
Mg
S
1

The bond order of \( \ce{C2} \) molecule, considering its molecular orbital configuration, is:

For \( \ce{C2} \): \( (\sigma 1s)^2 (\sigma^* 1s)^2 (\sigma 2s)^2 (\sigma^* 2s)^2 (\pi 2p_x)^2 (\pi 2p_y)^2 \). Bonding = 8, antibonding = 4. Bond order = \( \frac{8 - 4}{2} = 2 \).

1
3
2
1.5
3

Which molecule has a double bond formed by sharing two electron pairs?

In \( \ce{CO2} \), carbon forms two double bonds with oxygen atoms, each involving two shared electron pairs.

\( \ce{CO2} \)
\( \ce{H2} \)
\( \ce{Cl2} \)
\( \ce{NH3} \)
1

The shape of \( \ce{OF2} \) molecule is:

In \( \ce{OF2} \), oxygen is \( sp^3 \) hybridized with 4 electron pairs (2 bonding, 2 lone), resulting in a bent shape.

Linear
Trigonal planar
Tetrahedral
Bent
4

The hybridization of sulfur in \( \ce{SCl2} \) is:

In \( \ce{SCl2} \), sulfur has 4 electron pairs (2 bonding, 2 lone), requiring \( sp^3 \) hybridization, forming a bent shape.

\( sp^2 \)
\( sp \)
\( sp^3d \)
\( \ce{sp^3} \)
4

Which molecule has a bond angle of approximately 98° due to two lone pairs on the central atom?

In \( \ce{SF2} \), sulfur is \( sp^3 \) hybridized with 4 electron pairs (2 bonding, 2 lone), forming a bent shape. The F-S-F bond angle is ~98°, reduced from 104.5° in \( \ce{H2O} \) due to increased lone pair repulsion from electronegative fluorine atoms.

\( \ce{H2O} \)
\( \ce{NH3} \)
\( \ce{SF2} \)
\( \ce{CH4} \)
3

The total number of sigma bonds in \( \ce{C4H8} \) (cyclobutane) is:

In \( \ce{C4H8} \) (cyclobutane), there are 4 \( \ce{C-C} \) sigma bonds in the ring and 8 \( \ce{C-H} \) sigma bonds, totaling 12 sigma bonds.

11
12
13
10
2

Which type of bond is represented by a dotted line in molecular structures?

A hydrogen bond, such as in \( \ce{HF} \), is depicted with a dotted line, indicating a weaker interaction than a covalent bond.

Covalent bond
Ionic bond
Hydrogen bond
Coordinate bond
3

What is the bond order of \( \ce{F2} \) molecule?

For \( \ce{F2} \): \( (\sigma 1s)^2 (\sigma^* 1s)^2 (\sigma 2s)^2 (\sigma^* 2s)^2 (\sigma 2p_z)^2 (\pi 2p_x)^2 (\pi 2p_y)^2 (\pi^* 2p_x)^2 (\pi^* 2p_y)^2 \). Bonding = 10, antibonding = 8. Bond order = \( \frac{10 - 8}{2} = 1 \).

2
1
3
0
2

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