Class 11 Chemistry MCQ – Bonding in Some Homonuclear Diatomic Molecules

This set of Class 11 Chemistry Chapter 4 Multiple Choice Questions & Answers (MCQs) focuses on “Bonding in Some Homonuclear Diatomic Molecules”.

1. What is the electronic configuration of hydrogen molecule?
a) σ1s2
b) σ1s1
c) σ1s
d) σ*1s
View Answer

Answer: a
Explanation: In a hydrogen atom, each hydrogen shares an electron from 1s orbital, so in total there are two electrons present in 1s bonding orbital of the molecule. So the electronic configuration of the hydrogen molecule is σ1s2.

2. What is the condition, for a molecule do not exist?
a) NA = NB
b) NA > NB
c) NA < NB
d) NA >/< NB
View Answer

Answer: a
Explanation: When a molecule’s bond order is equal to zero, the molecule cannot exist. The formula for finding out bond order is \(\frac{1}{2}\)(NB – NA). So NA – NB = 0, that is NA = NB. Where NA as the number of anti-bonding molecular orbitals and NB as the number of bonding molecular orbitals.

3. Which of the following molecule doesn’t exist?
a) O2
b) H2
c) He2
d) N2
View Answer

Answer: b
Explanation: The electronic configuration of He2 is σ1s2σ*1s2. Here NA = NB (where NA as the number of anti-bonding molecular orbitals and NB as the number of bonding molecular orbitals). So the molecule He2 doesn’t exist.
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4. The number of electrons in bonding orbital and anti-bonding orbital of Lithium molecule are ______ and _______ respectively.
a) 4, 4
b) 2, 2
c) 2, 4
d) 4, 2
View Answer

Answer: d
Explanation: The lithium molecule is denoted by Li2. When the lithium molecule is formed, each of the lithium shares an electron in the 2s orbital. Its electronic configuration is σ1s2σ*1s2σ2s2. So the number of electrons in bonding orbital and anti-bonding orbital of Lithium molecule are 4 and 2 respectively.

5. What is the electronic configuration of the carbon atom?
a) 1s22s22p2
b) σ1s2σ*1s2σ2s2σ*2s2π2px2π2py2
c) 1s22s22p1
d) σ1s2σ*1s σ2s2π2px2π2py2
View Answer

Answer: a
Explanation: The given question electronic configuration of carbon “atom”, but not carbon “molecule”. So by following Aufbau’s principle and noting that carbon contains 6 electrons, the answer is given as 1s22s22p2.

6. O2 is paramagnetic in nature.
a) True
b) False
View Answer

Answer: a
Explanation: σ1s2σ*1s2σ2s2σ*2s22pz2π2px2π2y2π*2px1π*2py1 is the electronic configuration of O2 molecule. According to this, it has two unpaired electrons, making it paramagnetic and is attracted by the magnetic field.

7. The electronic configurations of molecules change when the number of electrons is ________
a) 10
b) 20
c) 17
d) 14
View Answer

Answer: d
Explanation: The electronic configuration below number of electrons = 14, i.e. number of electrons = 12 is σ1s2σ*1s2σ2s2 σ*2s2π2px2π2y2but after 14, take number of electrons = 16 is σ1s2σ*1s2σ2s2σ*2s22pz2π2px2π2y2π*2px1π*2py1 So the change comes near 2pz orbital’s place.
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8. Which of the following is true regarding nitrogen molecule.
a) Diamagnetic
b) Paramagnetic
c) Bond order is 2
d) Total number of electrons in the molecule is 13
View Answer

Answer: a
Explanation: The Nitrogen molecule N2 is diamagnetic in nature as it contains zero single electrons, all the electrons are paired. Its bond order is calculated as 3 and the total number of electrons the nitrogen molecule are 14.

9. H2, N2, O2 and Li2 are ______________
a) heteronuclear diatomic molecules
b) heteronuclear triatomic molecules
c) homonuclear diatomic molecules
d) homonuclear triatomic molecules
View Answer

Answer: c
Explanation: The molecules that have the same atoms in them are called as homonuclear molecules. The molecules that have only two atoms are called diatomic molecules. So H2, N2, O2, and Li2 are called homonuclear diatomic molecules.
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10. What is the total number of electrons in the Chlorine molecule?
a) 17
b) 34
c) 18
d) 16
View Answer

Answer: b
Explanation: A Chlorine atom is made up of 17 electrons. When two Chlorine atoms share an electron covalently, the Chlorine molecule is formed. So the Chlorine molecule Cl2 has a total of 17 + 17 atoms = 34 atoms.

Sanfoundry Global Education & Learning Series – Chemistry – Class 11.

To practice all chapters and topics of class 11 Chemistry, here is complete set of 1000+ Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

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