Question

The electronic configuration of gadolinium (Atomic number 64) is ______.

Options

• [Xe] 4f³ 5d⁵ 6s²

• [Xe] 4f⁷ 5d² 6s¹

• [Xe] 4f⁷ 5d¹ 6s²

• [Xe] 4f⁸ 5d⁶ 6s²

• [Xe] 4f⁸ 5d⁹ 6s²

• [Xe] 4f⁶ 5d² 6s²

Answer 1

The electronic configuration of gadolinium (Atomic number 64) is [Xe] 4f⁷ 5d¹ 6s².

Explanation:

The electronic configuration of La (Z = 57) is [Xe] 5d¹ 6s². Therefore, further addition of electrons occurs in the lower energy 4f-orbital till it is exactly half-filled at Eu (Z = 63). Thus, the electronic configuration of Eu is [Xe] 4f⁷ 6s². Thereafter, the addition of the next electron does not occur in the more stable, exactly half-filled 4f⁷ shell but occurs in the slightly higher energy 5d-orbital. Thus, the electronic configuration of Gd (Z = 64) is [Xe] 4f⁷ 5d¹ 6s².