Question

Lanthanoid elements have

• A. 14 electrons in the sixth period (atomic no. 90 to 103) that are filling 4f sublevel
• B. 14 electrons in the seventh period (atomic number = 90 to 103) that are filling 5f sublevel.
• C. 14 electrons in the sixth period (atomic number = 58 to 71) that are filling the 4f sublevel.
• D. 14 electrons in the seventh period (atomic number = 50 to 71) that are filling 4f sublevel.

Answer 1

The correct option is C

14 electrons in the sixth period (atomic number = 58 to 71) that are filling the 4f sublevel.

Definition