Question

Given below are two statements:
Statement I: Ferromagnetism is considered as an extreme form of paramagnetism.
Statement II: The number of unpaired electrons in a $Cr^{2+}$ ion (Z = 24) is the same as that of a $Nd^{3+}$ ion (Z = 60).
In the light of the above statements, choose the correct answer from the options given below:

• A. Both Statement I and Statement II are false
• B. Statement I is true but Statement II is false
• C. Statement I is false but Statement II is true
• D. Both Statement I and Statement II are true

Hint:

To determine the number of unpaired electrons in ions, subtract electrons based on ion charge and refer to orbital filling rules (3d, 4f, etc.).

Answer 1

The Correct Option is B

Statement I: Ferromagnetism is an extreme form of paramagnetism.

Paramagnetic materials have randomly oriented magnetic moments that align with an external magnetic field. Ferromagnetic materials exhibit spontaneous alignment of magnetic moments without an external field, leading to significantly stronger magnetization. Thus, ferromagnetism is indeed an extreme case of paramagnetism, making this statement correct.

Statement II: The number of unpaired electrons in Cr²⁺ (Z = 24) is equal to that in Nd³⁺ (Z = 60).

The electron configuration of Cr (Z = 24) is [Ar] 3d⁵ 4s¹. Cr²⁺ loses the 4s electron and one 3d electron, resulting in the configuration [Ar] 3d⁴, which has four unpaired electrons.

The electron configuration of Nd (Z = 60) is [Xe] 4f⁴ 6s². Nd³⁺ loses the two 6s electrons and one 4f electron, resulting in the configuration [Xe] 4f³, which has three unpaired electrons.

Consequently, the number of unpaired electrons is not the same.

Statement I is TRUE, Statement II is FALSE.