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 considered as an extreme form of paramagnetism.

In paramagnetism, the magnetic moments of individual atoms or ions are randomly oriented, but they tend to align with an external magnetic field. In ferromagnetism, there is spontaneous alignment of the magnetic moments, even in the absence of an external field, resulting in a much stronger magnetization.
Therefore, Ferromagnetism is considered as an extreme case of Paramagnetism, making the statement accurate.

Statement II: The number of unpaired electrons in a Cr²⁺ ion (Z = 24) is the same as that of a Nd³⁺ ion (Z = 60).

Cr (Chromium) has an electronic configuration of [Ar] 3d⁵ 4s¹. When it becomes Cr²⁺, it loses the 4s electron and one 3d electron giving [Ar] 3d⁴, resulting in four unpaired electrons.

Nd (Neodymium) has an electronic configuration of [Xe] 4f⁴ 6s². When it becomes Nd³⁺, it loses the two 6s electrons and one 4f electron giving [Xe] 4f³, resulting in three unpaired electrons.

Therefore, the number of unpaired electrons is incorrect.

Statement I is TRUE, statement II is FALSE.