Free Atomic Structure MCQs with Answers

• A. 10
• B. 6
• C. 8
• D. 0

Explanation: The respective orbital where n = 3, l = 2 will be '3d' because 3d orbitals contain five subshells and the principal quantum number is 3.

• A. Aufbau Principle
• B. Hund's Rule
• C. Pauli's Exclusion Principle
• D. n+l Rule

Explanation: Hund's Rule is the correct answer as it deals with the arrangement of electrons in orbitals, which determines the number of unpaired…

• A. Principal quantum number (n)
• B. Magnetic quantum number (m)
• C. Spin quantum number (s)
• D. Azimuthal quantum number (l)

Explanation: Spin quantum number describes the intrinsic angular momentum of an electron or the spin of an electron, and it is not a direct consequence…

• A. 1
• B. 2
• C. 6
• D. 10

Explanation: The maximum number of electrons that can be accommodated in a 3s orbital is 2.

• A. A
• B. B
• C. C
• D. D

Explanation: A p orbital has a dumbbell shape, which consists of two lobes. These lobes are aligned along different axes.

• A. Increasing
• B. Decreasing
• C. Remains constant
• D. First increases than decreases

Explanation: As we move away from the nucleus, the distance between the adjacent orbits goes on increasing.

• A. Electron cloud
• B. Electron sea
• C. Sub-shell
• D. Sub-level

Explanation: An electron cloud can be thought of as a probability field, the area in space where an electron is likely to be.

• A. 4p
• B. 3d
• C. 4s
• D. 5d

Explanation: The atomic number of an element tells the number of protons in the nucleus of an atom.For manganese (Mn), with an atomic number of 25, the…

• A. 4
• B. 5
• C. 6
• D. 7

Explanation: To determine the number of unpaired d-electrons for an element with atomic number Z = 25, consider its electronic configuration.

• A. 2,0,0
• B. 3,0,0
• C. 2,1,1
• D. 3,1,0

Explanation: In a lithium (Li) atom, there are three electrons. To determine the correct set of quantum numbers for the unpaired electrons, we first…

• A. s - orbital
• B. p - orbital
• C. d - orbital
• D. f - orbital

Explanation: An electron having spin quantum number of s=+1/2 and magnetic quantum number m=+3 can be present in f orbital only because m=+3 is…

• A. 1,2
• B. 0,1,2
• C. 1,2,3
• D. 1,0,1

Explanation: The azimuthal quantum number (l) specifies the subshell within a principal energy level (n).

• A. 2
• B. 4
• C. 6
• D. 9

Explanation: Option D predicts 9 orbitals, which indeed corresponds to the correct number of orbitals using the formula ((2 times 3^2 = 18)) for the…

• A. position
• B. energy
• C. position and energy
• D. uncertainty

Explanation: So, the correct answer is:c) Position and EnergyQuantum numbers specify both the position and energy of an electron within an atom.

• A. [Ar]3d44s2
• B. [Ar]3d54s1
• C. [Ar]3d64s2
• D. [Ar]3d104s1

Explanation: An electron must be excited to 3d from 4s sub-shell as half filled subshells are more stable hence this configuration {[Ar]3d4,4s2} is…

• A. 9
• B. 7
• C. 2
• D. 5

Explanation: 4s is outer most shell of a neutral atom with one electron in 3d and 4s has 2 electrons hence the correct option is 'C'.

• A. He
• B. Na
• C. Mg
• D. K

Explanation: The valence shell electronic configuration of Mg is :3s2,hence this is the correct option.

• A. 2s and 3px
• B. 3dxy and 3dyz
• C. ls and 2s
• D. 4f and 5p.

Explanation: Principle quantum number indicates the energy level or shell in which an electron is located.3dxy and 3dyz both have the same energy level…

• A. 31H
• B. 42He+
• C. 11H+
• D. 21H-

Explanation: The electronic configuration of 21H- is : 1s2,hence it is the correct option.

• A. Sc+3
• B. Ti+4
• C. Ni+2
• D. Fe+2

Explanation: Electronic configuration of Ni+2 is :1s2,2s2,2p6,3s2,3p6,3d8.It has 8 electrons in 3d subshell which is highest among all the other…