Question

Match the following.

List - I	List - II
I) The electrons of same orbital differ in spin	a) Stability of half filled sublevel
II) Order of energy of orbitals is $2s,2p,3s,3p,4s$	b) Stability of completely filled sublevel
III) Electronic configuration of $N$ is $1s^{2}2s^{2}2p^3$	c) Pauli's principle
IV) Electric configuration of $Cu$ is [Ar] $4s^{1}3d^{10}$	d) Aufbau principle

• A. I-a II-b III-c IV-d
• B. I-d II-c III-b IV-a
• C. I-c II-d III-a IV-b
• D. I-c II-b III-d IV-a

Answer 1

Answer: (C)

I-c II-d III-a IV-b

I-c
The electrons of the same orbital differ in spin. Thus two electrons in a given orbital have opposite spins. This is in accordance with Pauli's principle.
II-d
Order of orbitals is $2s,2p,3s,3p,4s$. The orbitals are filled with electrons in order of the increasing energies. This is in accordance with Aufbau principle.
III-a
Electronic configuration of $N$ is $1s^{2}2s^{2}2p_x^{1}2p_y^{1}2p_z^1$
2p orbital contains 3 unpaired electrons. They have parallel spin.
IV-b
Electric configuration of $Cu$ is $\left[Ar\right]4s^{1}3d^{10}$ and not $\left[Ar\right]4s^{2}3d^9$ due to the stability of completely filled 3d sublevel .