Electronic Configuration

Diamagnetism is exhibited by species with all electrons paired (i.e., no unpaired electrons).

Let’s analyze electron configurations:

$%5Cmathrm%7BLa%7D$ : Atomic number 57. Configuration: [Xe] 5d $%5E%7B1%7D$ 6s $%5E%7B2%7D$
$%5CRightarrow%20%5Cmathrm%7BLa%5E%7B3%2B%7D%7D$ : Loses 3 electrons → [Xe] (no unpaired electrons) → Diamagnetic
$%5Cmathrm%7BCe%7D$ : Atomic number 58. Configuration: [Xe] 4f $%5E%7B1%7D$ 5d $%5E%7B1%7D$ 6s $%5E%7B2%7D$
$%5CRightarrow%20%5Cmathrm%7BCe%5E%7B4%2B%7D%7D$ : Loses 4 electrons → [Xe] (no unpaired electrons) → Diamagnetic
$%5Cmathrm%7BCe%5E%7B2%2B%7D%7D$ : Configuration after losing 2 electrons = [Xe] 4f $%5E%7B2%7D$ → 2 unpaired electrons → Paramagnetic
$%5Cmathrm%7BLu%5E%7B3%2B%7D%7D$ : Atomic number 71. Configuration: [Xe] 4f $%5E%7B14%7D$ 5d $%5E%7B1%7D$ 6s $%5E%7B2%7D$ , loses 3e⁻ → [Xe] 4f $%5E%7B14%7D$ (completely filled) → Diamagnetic
$%5Cmathrm%7BYb%5E%7B3%2B%7D%7D$ : Atomic number 70 → [Xe] 4f $%5E%7B13%7D$ , loses 3e⁻ → 4f $%5E%7B13%7D$ → one unpaired → Paramagnetic
$%5Cmathrm%7BLu%5E%7B2%2B%7D%7D$ : Configuration = [Xe] 4f $%5E%7B14%7D$ 5d $%5E%7B1%7D$ (one unpaired d-electron) → Paramagnetic
$%5Cmathrm%7BYb%5E%7B2%2B%7D%7D$ : Configuration = [Xe] 4f $%5E%7B14%7D$ (completely filled f-shell) → Diamagnetic

Conclusion: Only $%5Cmathrm%7BLa%5E%7B3%2B%7D%7D$ and $%5Cmathrm%7BCe%5E%7B4%2B%7D%7D$ are both diamagnetic.

Chapter Questions
1 MCQs