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 Cr²⁺ ion (Z = 24) is the same as that of a Nd³⁺ ion (Z = 60).
In the light of the above statements, choose the correct answer from the options given below:

CONCEPT:

Ferromagnetism and Electronic Configuration

• Ferromagnetism: It is a property of materials like iron, cobalt, and nickel, where magnetic moments of individual atoms align spontaneously in the same direction even in the absence of an external magnetic field. It is an extreme form of paramagnetism because the alignment of magnetic moments is much stronger and ordered in ferromagnetic substances compared to paramagnetic ones.
• Electronic Configuration of Ions:
  • For Cr²⁺ (Z = 24), the electronic configuration can be derived as:
    • Neutral Cr: [Ar] 3d⁵ 4s¹
    • After losing 2 electrons: Cr²⁺ = [Ar] 3d⁴
    • Number of unpaired electrons in 3d⁴ = 4
  • For Nd³⁺ (Z = 60), the electronic configuration is:
    • Neutral Nd: [Xe] 4f⁴ 6s²
    • After losing 3 electrons: Nd³⁺ = [Xe] 4f³
    • Number of unpaired electrons in 4f³ = 3

EXPLANATION:

• Statement I: "Ferromagnetism is considered as an extreme form of paramagnetism."
  • This statement is true because ferromagnetic materials exhibit a stronger and more ordered alignment of magnetic moments compared to paramagnetic materials. Ferromagnetism can be considered as an extreme or special case of paramagnetism.
• Statement II: "The number of unpaired electrons in a Cr²⁺ ion (Z = 24) is the same as that of a Nd³⁺ ion (Z = 60)."
  • This statement is false because:
    • Cr²⁺ has 4 unpaired electrons (from its 3d⁴ configuration).
    • Nd³⁺ has 3 unpaired electrons (from its 4f³ configuration).
    Hence, the number of unpaired electrons is not the same for Cr²⁺ and Nd³⁺.

Therefore, the correct answer is: Statement I is true but Statement II is false.