Chemical Bonding and Molecular Structure

The highest occupied molecular orbital for Ne2 is

1. *2p
2. 2p
3. 2p
4. *2p

Given below are two statements : In the light of the above statements, choose the most appropriate answer from the options given below:

1. Statement I is true but Statement II is false
2. Statement I is false but Statement II is true
3. Both Statement I and Statement II are true
4. Both Statement I and Statement II are false

The correct order of energies of molecular orbitals of N2 molecule, is

1. 1s < 1s < 2s < 2s < 2pz < ( 2px = 2py) < ( 2px = 2py) < 2pz
2. 1s < 1s < 2s < 2s < 2pz < 2pz < ( 2px = 2py) < ( 2px = 2py)
3. 1s < 1s < 2s < 2s < ( 2px = 2py) < ( 2px = 2py) < 2pz < 2pz
4. 1s < 1s < 2s < 2s < ( 2px = 2py) < 2pz < ( 2px = 2py) < 2pz

Which amongst the following is incorrect statement?

1. The bond orders of O2+, O2, O2- and O22- are 2.5, 2, 1.5 and 1, respectively
2. C2 molecule has four electrons in its two degenerate molecular orbitals
3. H2+ ion has one electron
4. O2+ ion is diamagnetic

Identify a molecule which does not exist.

1. Li2
2. C2
3. O2
4. He2

Which of the following diatomic molecular species has only bonds according to Molecular Orbital Theory?

1. C2
2. Be2
3. O2
4. N2

Consider the following species : CN+, CN-, NO and CN. Which one of these will have the highest bond order?

1. NO
2. CN-
3. CN+
4. CN

Which one of the following pairs of species have the same bond order ?

1. O2, NO+
2. CN-, CO
3. N2, O2-
4. CO, NO

Decreasing order of stability of O2, O2-, O2+ and O22- is

1. O22- > O2- > O2 > O2+
2. O2 > O2+ > O22- > O2-
3. O2- > O22- > O2+ > O2
4. O2+ > O2 > O2- > O22-

The correct bond order in the following species is

1. O2+ < O2- < O22+
2. O2- < O2+ < O22+
3. O22+ < O2+ < O2-
4. O22+ < O2- < O2+

Which of the following options represents the correct bond order ?

1. O2- > O2 < O2+
2. O2- < O2 > O2+
3. O2- > O2 > O2+
4. O2- < O2 < O2+

Which of the following is paramagnetic?

1. CN-
2. NO+
3. CO
4. O2-

The pair of species that has the same bond order in the following is

1. CO, NO+
2. NO-, CN-
3. O2, N2
4. O2, B2

In which of the following ionization processes the bond energy increases and the magnetic behaviour changes from paramagnetic to diamagnetic.

1. O2 O2+
2. C2 C2+
3. NO NO+
4. N2 N2+

During change of O2 to O2- ion, the electron adds on which one of the following orbitals ?

1. * orbital
2. orbital
3. * orbital
4. orbital

Four diatomic species are listed below. Identify the correct order in which the bond order is increasing in them

1. NO < O2- < C22- < He2+
2. O2- < NO < C22- < He2+
3. C22- < He2+ < O2- < NO
4. He2+ < O2- < NO < C22-

Bond order of 1.5 is shown by

1. O2+
2. O2-
3. O22-
4. O2

The pair of species with the same bond order is

1. O22-, B2
2. O2+, NO+
3. NO, CO
4. N2, O2

The pairs of species of oxygen and their magnetic behaviours are noted below. Which of the following presents the correct description?

1. O2-, O22- – Both diamagnetic
2. O2+, O2 – Both paramagnetic
3. O, O22- – Both paramagnetic
4. O+, O22- – Both paramagnetic

Which of the following has the minimum bond length ?

1. O2+
2. O2-
3. O22-
4. O2

The pairs of species of oxygen and their magnetic behavior are noted below. Which of the following presents the correct description?

1. O2-, O22- - Both diamagnetic
2. O+, O22- - Both paramagnetic
3. O2+, O2 - Both paramagnetic
4. O, O22- - Both paramagnetic

Which one of the following species does not exist under normal conditions?

1. Be2+
2. Be2
3. B2
4. Li2

According to MO theory which of the lists ranks the nitrogen species in terms of increasing bond order ?

1. N22- < N2- < N2
2. N2 < N22- < N2-
3. N2- < N22- < N2
4. N2- < N2 < N22-

Four diatomic species are listed below. Identify the correct order in which the bond order is increasing in them

1. NO < O2- < C22- < He2+
2. O2- < NO < C22- < He2+
3. C22- < He2+ < O2- < NO
4. He2+ < O2- < NO < C22-

Main axis of a diatomic molecule is z, atomic orbitals px and py overlap to form which of the following orbitals.

1. molecular orbital
2. molecular orbital
3. molecular orbital
4. No bond will form

Right order of dissociation energy N2 and N2+ is

1. N2 > N2+
2. N2 = N2+
3. N2+ > N2
4. none

Which species does not exhibit paramagnetism?

1. N2+
2. O2-
3. CO
4. NO