Features of MOT

Q.

The increasing order of the bond order of ${\mathrm{O}}_2$, ${\mathrm{O}}_2^{-}$, ${\mathrm{O}}_2^{+}$ and ${\mathrm{O}}_2^{2-}$?

Q. The total number of atomic orbitals in fourth energy level of an atom is

1. 8
2. 16
3. 32
4. 4

Q.

What is the HOMO-LUMO gap and how does it change the properties of a substance?

Q.

Which of the following arrangements does not represent the correct order of property stated against it?

1. $\mathrm{Sc}<\mathrm{Ti}<\mathrm{Cr}<\mathrm{Mn}$: Number of oxidation states

2. ${\mathrm{Ni}}^{2+}<{\mathrm{Co}}^{2+}<{\mathrm{Fe}}^{2+}<{\mathrm{Mn}}^{2+}$: Ionic size

3. ${\mathrm{V}}^{2+}<{\mathrm{Cr}}^{3+}<{\mathrm{Mn}}^{2+}<{\mathrm{Fe}}^{2+}$: Paramagnetic behavior

4. ${\mathrm{Co}}^{3+}<{\mathrm{Fe}}^{3+}<{\mathrm{Cr}}^{3+}<{\mathrm{S}}^{3+}$: Stability in aqueous solution

Q.

Explain The Formation Of The Hydrogen Molecules With A Diagram

Q. Which of the following molecular orbital has 2 nodal planes?

1. $\sigma 2s$
2. $\pi 2p_y$
3. ${\pi }^{\ast }2p_y$
4. ${\sigma }^{\ast }2p_x$

Q. According to Molecular Orbital Theory

1. $C_2^{2-}$ is expected to be diamagnetic
2. $O_2^{2+}$ expected to have a longer bond length than $O_2$
3. $N_2^{+}$ and $N_2^{-}$ have the same bond order
4. $H{e}_2^{+}$ has the same energy as two isolated $He$ atoms

Q.

What are Paramagnetic substances?

Q.

Both ionic & covalent bonds are present in _____

1. KCl

2. NaOH

3. CH₄

4. SO₂

Q.

The correct order of bond strength is $N_2^{+},N_2$ and $N_2^{-}$

1. $N_2^{+}>N_2>N_2^{-}$

2. $N_2^{-}>N_2>N_2^{+}$

3. $N_2>N_2^{+}>N_2^{-}$

4. $N_2^{-}>N_2^{+}>N_2$

Q.

Write the significance of a plus and a minus sign shown in representing the orbitals.

Q.

Give two examples of each of the following: Tetravalent element.

Q. If $z$ axis is the molecular axis then $\pi$ orbitals are formed via the overlap of-

1. $s+p_z$
2. $p_x+p_y$
3. $p_z+p_z$
4. $p_x+p_x$

Q.

The wave function of a molecular orbital formed by reinforcing of wave functions of ΨA and ΨB of atomic orbitals A and B is represented as

a) Φ= ΨA + ΨB

b) Φ= ΨA - ΨB

c) Φ= ΨA * ΨB

d) None of the above

Q. In the following questions a statement of assertion $\left(A\right)$ followed by a statement of reason $\left(R\right)$ is given. Choose the correct option out of the choices given below each question. Assertion$\left(A\right)$: Among halogens fluorine is the best oxidant. Reason$\left(R\right)$: Fluorine is the most electronegative atom.

1. Both $A$ and $R$ are true and $R$ is the correct explanation of $A$.
2. Both $A$ and $R$ are true and $R$ is not the correct explanation of $A$.
3. Both $A$ and $R$ are false.
4. $A$ is true but $R$ is false.

Q. During the formation of a molecular orbital from atomic orbitals of the same atom probability of electron density is -

1. Zero in the molecular plane
2. Maximum in the nodal plane
3. Zero in the nodal plane
4. Zero in the surface of the lobe

Q. Tertiary amines have lowest boiling points amongst isomeric amines because:

1. they have highest molecular mass
2. they do not form hydrogen bonds
3. they are more polar in nature
4. they are most basic in nature

Q. Which of the following statements is correct regarding molecular orbital theory (MOT)?

1. Energy of bonding orbital is more than that of anti-bonding orbital
2. Bonding orbitals are monocentric
3. Energy of bonding orbital is less than that of anti-bonding orbital
4. Bonding orbitals follow (n+ l) rule
   

Q. Assertion : In the bonding molecular orbital (MO) of $H_2$, the electron density is increased between the nuclei.
Reason : The bonding MO is ${\psi }_A+{\psi }_B$, which shows destructive interference of the combining electron waves.

1. Assertion is incorrect, reason is correct
2. Assertion is correct, reason is incorrect
3. Assertion and reason are correct and reason is the correct explanation for the assertion
4. Assertion and reason are correct, but reason is not the correct explanation for the assertion.

Q. Which of the following statement is incorrect regarding bonding molecular orbital?

1. Molecular orbitals are formed by the overlap of in-phase wave forms
2. It is lower in energy when compared to atomic orbitals
3. Electron density increases in the inter-nuclear region
4. Results in the formation of a destabilized molecular orbital (M.O.)

Q.

Question 32

Using molecular orbital theory, compare the bond energy and magnetic character of $O_2^{+}$ and $O_2^{+}$ species.

Q. According to the molecular orbital theory the shape and size of molecular orbital depends upon-

1. Shape and size of combining atomic orbitals.
2. Numbers of the combining atomic orbitals.
3. Orientation of the combining atomic orbitals.
4. All of the above.

Q. Bond order depends on the number of bonding and anti-bonding orbitals. The bond order can never have:

1. A negative value
2. An integral value
3. Assume any positive, or an integral, or a fractional value including zero
4. a non zero value

Q.

Which of the following has least bond dissociation energy ?

1. ${\mathrm{F}}_2$

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

3. ${\mathrm{I}}_2$

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

Q. Paramagnetism is exhibited by the molecules which:

1. are not attracted by magnetic field
2. contains only paired electrons
3. carries a positive charge
4. contains unpaired electrons

Q. 46. Highest C-O bond length found in 1) [Mn(CO)6]+ 2) [Cr(CO)6] 3) [V(CO)6]- 4) same in all.

Q.

Which one of the following is an incorrect orbital notation?

1. $2\mathrm{s}$

2. $4{\mathrm{d}}_{\mathrm{xy}}$

3. $3\mathrm{f}$

4. $4\mathrm{s}$

Q.

Which overlapping is strongest?

Q. The difference in energy between the molecular orbital formed and combining atomic orbital is called-

1. Activation energy
2. Stabilization energy
3. Bond energy
4. Destabilization energy

Q. Draw molecular orbital diagram of $O_2$ or $N_2$ with magnetic behavior and bond order.