Question

The f-orbitals are half and completely filled respectively in lanthanide ions:

(Given: Atomic no. Eu = 63, Sm = 62, Tm = 69, Tb = 65, Yb = 70, Dy = 66)

Options

• Eu⁺² and Tm⁺²

• Sm⁺² and Tm⁺²

• Tb⁺⁴ and Yb⁺²

• Dy⁺² and Yb⁺²

Answer 1

Tb⁺⁴ and Yb⁺²

Explanation:

In lanthanide ions, electrons are filled in the 4f-orbitals. A half-filled 4f subshell has 7 electrons (4f⁷) and is very stable. A completely filled 4f subshell, which has 14 electrons (4f¹⁴), is also very stable.