Molecular Orbital Energy Diagrams

Q.

Which one of the following is paramagnetic?

1. ${\mathrm{O}}_3$

2. ${\mathrm{N}}_2$

3. $\mathrm{CO}$

4. ${\mathrm{O}}_2$

Q. Oxidation state of Fe in Fe(CO)_{5. Reason.}

Q.

Calculate the bond order of ${\mathrm{He}}_2$.

Q.

Using MOT, predict which of the following species has the shortest bond length ?

1. $O_2^{+}$
2. $O_2^{-}$
3. $O_2^{2-}$
4. $O_2^{2+}$

Q. Which of the following statement is incorrect?

1. During $N_2^{+}$ formation, one electron is removed from the bonding molecular orbital of $N_2$
2. During $O_2^{+}$ formation, one electron is removed from the antibonding molecular orbital of $O_2$
3. During $O_2^{-}$ formation, one electron is added to the bonding molecular orbital of $O_2$
4. During $N_2^{-}$ formation, one electron is added to the antibonding molecular orbital of $N_2^{-}$

Q.

Sir/Madam

In the structure of copper sulphate(CuSO4.5H2o), 4 water molecules are coordinated and 1 is hydrogen bonded. The electronic configuration of Cu is [Ar]4s¹ 3d¹⁰ ​​^{​​​​​}​​​​​​. When the water molecules are sharing 8 electrons, it becomes 4s2 3d10 4p6 5s1. When cu becomes cu2+ion, the configuration becomes 4s2 3d10 4p5. But these 2 configurations aren't stable. Then why did cuso4.5h2o occurs at a reasonably good amount in nature. Kindly explain in "detail"?

Q. The relative energies of molecular orbitals are found to be in increasing order as follows- $\sigma \left(1s\right)<{\sigma }^{\ast }\left(1s\right)<\sigma \left(2s\right)<{\sigma }^{\ast }\left(2s\right)<\left[\pi \right(2p_y\left)\pi \right(2p_z\left)\right]<\sigma \left(2p_x\right)<\left[{\pi }^{\ast }\right(2p_y\left){\pi }^{\ast }\right(2p_z\left)\right]<{\sigma }^{\ast }\left(2p_x\right)$

1. For $O_2$ to $N{e}_2$
2. For $H_2$ to $N_2$
3. For $H_2$ to $N{e}_2$
4. For $N_2$ to $N{e}_2$

Q.

Give the number of electrons in the species $H_2^{+},H_{2}and{O}_2^{+}$

Q. Identify the molecule with p-p orbital overlapping.

1. Hydrogen
2. Hydrogen bromide
3. Hydrogen chloride
4. Chlorine

Q. Which of the following molecules/species have identical bond order and magnetic properties?
(I) $O_2^{+}$
(II) $NO$
(III) $N_2^{+}$

1. (I), (II) only
2. (I), (III) only
3. (I), (II) and (III)
4. (II) and (III) only

Q. E⁰ (Fe³⁺/Fe²⁺) is positive . This means Fe can be reduced to +2 from +3 but then enthalpy of hydration is also negative ( when oxidizing Fe+2 to Fe+3 because Fe+3 has more charge density so it will make system stable nd release energy). Then why is E⁰(Fe3+/Fe2+) positive?

Q.

Assuming that Hund’s rule is violated, the bond order and magnetic nature of the diatomic molecule $B_2$ is :

1. 1 and diamagnetic

2. 0 and diamagnetic

3. 1 and paramagnetic

4. 0 and paramagnetic

Q. Which of the following statements is incorrect?

1. Among $O_2^{+},O_2$ and $O_2^{-}$ the stability decreases as $O_2^{+}>O_2>O_2^{-}$
2. $H{e}_2$ molecule does not exist as the effect of bonding and anti-bonding orbitals cancel each other.
3. $C_2,O_2^{2-}$ and $L{i}_2$ are diamagnetic
4. In $F_2$ molecule, the energy of ${\sigma }_{2p_z}$ is more than ${\pi }_{2p_x}$ and ${\pi }_{2p_y}$

Q. Degeneracy of H atom in 3rd excited State is
1) 16
2) 10
3) 12
4) 9

Q.

Is $C{o}^{3+}$ Paramagnetic Or Diamagnetic?

Q.

The common features of the species ${{\mathrm{N}}_2}^{2-}$ , ${\mathrm{O}}_2$ and ${\mathrm{NO}}^{-}$ are

1. bond order is three and are isoelectronic

2. bond order is two and are isoelectronic

3. bond order is three but are not isoelectronic

4. bond order is two but are not isoelectronic

Q.

Is $\mathrm{Zn}$ paramagnetic or diamagnetic?

Q. The colour of $X_2$ molecules of group 17 elements changes gradually from yellow to violet down the group. This is due to:

1. The physical state of $X_2$ at room temperature changes from gas to solid down the group
2. The decrease in HOMO-LUMO gap down the group
3. The decrease in ${\pi }^{\ast }-{\sigma }^{\ast }$ gap down the group
4. The decrease in ionization energy down the group

Q.

Oxygen is a diatomic molecule.

1. True
2. False

Q. The X-X bond length is 1.5 and Y-Y length is 1.48. If electronegativity values of X and Y are 3 and 3.5 respectively then Y-X Bond length would be-> A)1.44 B)0.98 C) 1.75 D)0.73

Q. Which of the following molecule(s) is expected to exhibit diamagnetic behaviour?

1. $C_2$
2. $O_2$
3. $N_2$
4. $S_2$

Q. The number of unpaired electrons in a diatomic molecule of an element with atomic number 8 is:

1. 3
2. 2
3. 4
4. 1

Q. Which of the following species is paramagnetic in nature

1. $B_2$
2. $O_2^{2-}$
3. $N_2$
4. $H{e}_2$

Q.

The bond order of the species with orbital configuration ($\sigma$${}_{1s}$)${}^2$($\sigma$${}^{\ast }$${}_{1s}$)${}^2$.($\sigma$${}_{2s}$)${}^2$($\sigma$${}^{\ast }$${}_{2s}$)${}^2$($\sigma$${}^{\ast }$${}_{2pz}$)${}^1$ will
be

1. 1/2

2. 2

3. 3

4. Zero

Q.

Which of the following molecules is paramagnetic?

1. ${\mathrm{O}}_3$

2. ${\mathrm{N}}_2$

3. $\mathrm{CO}$

4. $\mathrm{NO}$

Q.

Select the correct statement for non-bonding and anti-bonding orbitals:

1. Non - bonding orbitals have same energy as that of the atomic orbitals from which they are formed.

2. Anti - bonding orbitals have higher energy than the atomic orbitals from which they are formed

3. Non - bonding orbital have higher energy than the atomic orbitals from which they are formed

4. Anti - bonding orbital have lower energy than the atomic orbitals from which they are formed

Q. From molecular orbital theory we can give the electronic configuration of singly positive Nitrogen molecular ion $N_2^{+}$ as-

1. $\sigma \left(1s{)}^2{\sigma }^{\ast }\right(1s{)}^2\sigma \left(2s{)}^2{\sigma }^{\ast }\right(2s{)}^2\pi \left(2p{)}^4\sigma \right(2p{)}^1$
2. $\sigma \left(1s{)}^2{\sigma }^{\ast }\right(1s{)}^2\sigma \left(2s{)}^2{\sigma }^{\ast }\right(2s{)}^2\sigma \left(2p{)}^1\pi \right(2p{)}^3$
3. $\sigma \left(1s{)}^2{\sigma }^{\ast }\right(1s{)}^2\sigma \left(2s{)}^2{\sigma }^{\ast }\right(2p{)}^2\pi (2p{)}^4$
4. $\sigma \left(1s{)}^2{\sigma }^{\ast }\right(1s{)}^2\sigma \left(2s{)}^2{\sigma }^{\ast }\right(2s{)}^2\sigma \left(2p{)}^2\pi \right(2p{)}^2$

Q. The colour of $X_2$ molecules of group 17 elements changes gradually from yellow to violet down the group. This is due to:

1. The physical state of $X_2$ at room temperature changes from gas to solid down the group
2. The decrease in HOMO-LUMO gap down the group
3. The decrease in ${\pi }^{\ast }-{\sigma }^{\ast }$ gap down the group
4. The decrease in ionization energy down the group

Q. using mo theory , explain that f2 molecule has single bond, o2 molecule has double bond while n2 molecules has triple bond

Q. Which of the following represents the correct order of filling the molecular orbitals of $B_2,C_2$ and $N_2$ ?

1. ${\pi }_{2p_x}={\pi }_{2p_y}<{\sigma }_{2p_z}<{\pi }_{2p_x}^{\ast }={\pi }_{2p_y}^{\ast }<{\sigma }_{2p_z}^{\ast }$
2. ${\sigma }_{2p_z}<{\pi }_{2p_x}={\pi }_{2p_y}<{\pi }_{2p_x}^{\ast }={\pi }_{2p_y}^{\ast }<{\sigma }_{2p_z}^{\ast }$
3. ${\sigma }_{2p_z}={\pi }_{2p_x}={\pi }_{2p_y}<{\pi }_{2p_x}^{\ast }={\pi }_{2p_y}^{\ast }<{\sigma }_{2p_z}^{\ast }$
4. ${\pi }_{2p_x}<{\pi }_{2p_y}={\sigma }_{2p_z}>{\pi }_{2p_y}^{\ast }<{\pi }_{2p_x}^{\ast }={\sigma }_{2p_z}^{\ast }$