Quantum Numbers

Q. The magnitude of the orbital angular momentum of an electron is given by $L=\frac{\sqrt{5}h}{\pi }$. How many orbitals of this kind are possible for the subshell?

1. 4
2. 9
3. 11
4. 5

Q.

What is the electron configuration of ${\mathrm{Cr}}^{3+}$?

Q. Number of orbitals represented by $n=3,l=2$ and $m=+2$ is:

1. $7$
2. $5$
3. $1$
4. $3$

Q. Maximum number of electrons in an atom that can have the quantum numbers $n=4,m_e=+1$ is:

1. 3
2. 5
3. 6
4. 8

Q.

The time period of revolution of electron in its ground state orbit in a hydrogen atom is 1.6 × 10⁻¹⁶s. The frequency of revolution of the electron in its first excited state (in s⁻¹) is

1. 6.2 × 10¹⁵

2. 7.8 × 10¹⁴

3. 1.6 × 10¹⁴

4. 5.6 × 10¹²

Q. The number of orbitals associated with quantum numbers $n=5,m_s=+\frac{1}{2}$ is:

1. $25$
2. $50$
3. $11$
4. $15$

Q.

Maximum number of electrons in a subshell with l = 3 and n = 4 is:

1. 14

2. 16

3. 10

4. 12

Q. The spin angular momentum for the ${}^{\prime }{s}^{\prime }$ electron in $H-atom$ is:

1. $\frac{\sqrt{3}h}{4\pi }$
2. $\sqrt{h}2\pi$
3. $\sqrt{h}4\pi$
4. $\frac{\sqrt{3}h}{2\pi }$

Q. The maximum number of electrons that can have principal quantum number, n = 3 and spin quantum number, $m_s=-\frac{1}{2}$ is:

1. 6
2. 7
3. 8
4. 9

Q.

If each orbital can hold a maximum of 3 electrons. The number of elements in 2nd period of periodic table (long form) is? Why? Please explain.

Q.

How many electrons in an atom may have the following quantum numbers?
(a) n = 4, m=−12 m=-\frac{1}{2} m=−

​$\frac{1}{2}$
(b) n = 3, l = 0

Q.

4d, 5p, 5f, and 6p orbitals are arranged in order of decreasing energy. The correct option is:

1. 5f > 6p > 5p > 4d

2. 6p > 5f > 5p > 4d

3. 6p > 5f > 4d > 5p

4. 5f > 6p > 4d > 5p

Q. How many electrons can fit in the orbital for which n = 3 and l = 1 ?

1. 10
2. 14
3. 2
4. 6

Q. Which set of quantum number are not possible?

1. n = 3, l = 2, m = 0, $s=-\frac{1}{2}$
2. n = 3, l = 2, m = -2, $s=-\frac{1}{2}$
3. n = 3, l = 3, m = -3, $s=-\frac{1}{2}$
4. n = 3, l = 0, m = 0, $s=-\frac{1}{2}$

Q.

The pair of ions having same electronic configuration is __________.

1. ${\mathrm{Cr}}^{3+},{\mathrm{Fe}}^{3+}$

2. ${\mathrm{Fe}}^{3+},{\mathrm{Mn}}^{2+}$

3. ${\mathrm{Fe}}^{3+},{\mathrm{Co}}^{3+}$

4. ${\mathrm{Sc}}^{3+},{\mathrm{Cr}}^{3+}$

Q. Which one of the quantum numbers describes shape of an orbital?

1. Azimuthal quantum number
2. Magnetic quantum number
3. Principal quantum number
4. Spin quantum number

Q.

A gas absorbs a photon of 355 nm and emits it at two wavelengths. If one of the emissions is at 680 nm, what will be the next wavelength emitted?

Q.

On the basis of quantum numbers, justify that the sixth period of the periodic table should have 32 elements.

Q.

What are the nodal planes of ${\mathrm{dz}}^2$ orbital? How can we find nodal planes?

Q. The correct set of quantum numbers for the unpaired electron of chlorine atom (Z=17) is:

1. n=2, l=1, m=1
2. n=2, l=1, m=0
3. n=3, l=1, m=1
4. n=3, l=0, m=0

Q. What do you mean by pseudo noble gas configuration

Q. Which of the following set of quantum numbers is correct for an electron in 5d orbital?

1. $n=5,l=4,m=3,s=+\frac{1}{2}$
2. $n=5,l=2,m=3,s=+\frac{1}{2}$
3. $n=5,l=2,m=2,s=+\frac{1}{2}$
4. $n=5,l=3,m=2,s=+\frac{1}{2}$

Q. Which shell would be the first to have a g subshell?

1. M
2. O
3. L
4. N

Q.

Using s, p, d notations, describe the orbital with the following quantum numbers.
(a) n = 1, l = 0; (b) n = 3; l =1 (c) n = 4; l = 2; (d) n = 4; l =3.

Q.

If elements with principal quantum number $n>4$ were not allowed in nature, the number of possible elements would have been :

1. 60
2. 44
3. 108
4. 40

Q. Which of the following represents an incorrect set of quantum numbers?

1. $n=4,l=2,m=2,s=+\frac{1}{2}$
2. $n=5,l=3,m=4,s=+\frac{1}{2}$
3. $n=4,l=3,m=1,s=+\frac{1}{2}$
4. $n=5,l=3,m=3,s=+\frac{1}{2}$

Q.

Question 21

Which of the following statements concerning the quantum numbers are correct ?

(a) The angular momentum quantum number determines the three-dimensional shape of the orbital

(b) The principal quantum number determines the orientation and energy of the orbital

(c) Magnetic quantum number determines the size of the orbital.

(d). Spin quantum number of an electron determines the orientation of the spin of electron relative to the chosen axis.

Q.

Orbital angular momentum depends on _____?

Q. If n and l are respectively the principal and azimuthal quantum numbers, then the expressions for calculating the total number of electrons in any shell is:

1. $\sum _{l=1}^{l=n}$ $2(2l+1)$
2. $\sum _{l=1}^{l=n-1}$ $2(2l+1)$
3. $\sum _{l=0}^{l=n+1}$ $2(2l+1)$
4. $\sum _{l=0}^{l=n-1}$ $2(2l+1)$

Q. The total number of electrons in $C{O}_2$ are

1. 22
2. 44
3. 66
4. 88