Question

General electronic configuration of lanthanides is

• A. (n – 2) f ^1–14 (n – 1) s² p6 d^0–1 ns²
• B. (n – 2) f ^10–14 (n – 1) d^0–1 ns²
• C. (n – 2) f ^0–14(n – 1) d¹⁰ ns²
• D. (n – 2) d0–1 (n – 1) f 1–14 ns2

Answer 1

The Correct Option is A

Let's explore the electronic configuration of lanthanides to understand why the correct answer is (n – 2) f ^1–14 (n – 1) s² p6 d^0–1 ns².

Lanthanides are elements with atomic numbers from 57 to 71, starting with Lanthanum (La) and ending with Lutetium (Lu). They are characterized by the filling of the 4f orbitals. Here's the detailed explanation:

1. Lanthanides start filling the 4f subshell after the 6s orbital is filled. The 4f orbitals are part of the (n – 2) level, which is why these are written as (n – 2)f.
2. The general electronic configuration of lanthanides must account for the partial filling of f orbitals, hence 4f^1–14 for La to Lu.
3. The (n – 1) p orbitals, specifically 5d in lanthanides, can be either completely unoccupied or singly occupied (hence d^0–1), usually filled when outer 6s fills prior.
4. Lanthanides generally complete the 5d orbitals in Lanthanum and then fill the 4f orbitals in the subsequently heavier elements.

Let's go through the provided options:

• Option 1: (n – 2) f ^1–14 (n – 1) s² p6 d^0–1 ns²
  This option accurately represents the lanthanide series' electronic configuration and accounts for filling in d orbitals and subsequent f filling.
• Option 2: (n – 2) f ^10–14 (n – 1) d^0–1 ns²
  This starts filling 4f from the 10th, which is not correct, as lanthanides start from 1st.
• Option 3: (n – 2) f ^0–14 (n – 1) d¹⁰ ns²
  Suggests a complete fill of (n–1) d orbitals, which is not typical for lanthanides.
• Option 4: (n – 2) d^0–1 (n – 1) f ^1–14 ns²
  Mistakenly interchanges positions of orbitals, having f at (n – 1).

Hence, the correct and scientifically verified electronic configuration of lanthanides is: (n – 2) f ^1–14 (n – 1) s² p6 d^0–1 ns².