Match the ions in Column I with their spin-only magnetic moments (BM) in Column II. Column I: P = Ce^3+ (Z = 58), Q = Nd^3+ (Z = 60), R = Sm^3+ (Z = 62), S = Gd^3+ (Z = 64). Column II: 1 = 5.92, 2 = 1.73, 3 = 7.94, 4 = 3.87.

JEE Advanced levelSingle correct optionDifficulty 3 of 3df204

Match the ions in Column I with their spin-only magnetic moments (BM) in Column II. Column I: P = $Ce X^{3 +}$ (Z = 58), Q = $Nd X^{3 +}$ (Z = 60), R = $Sm X^{3 +}$ (Z = 62), S = $Gd X^{3 +}$ (Z = 64). Column II: 1 = 5.92, 2 = 1.73, 3 = 7.94, 4 = 3.87.

Ions are

4 f^{1}

4 f^{3}

4 f^{5}

and

4 f^{7}

with 1, 3, 5 and 7 unpaired electrons. Using

n (n + 2)

: n = 1 gives 1.73, n = 3 gives 3.87, n = 5 gives 5.92 and n = 7 gives 7.94 BM. Hence P-2, Q-4, R-1, S-3.