The Lanthanoid series consists of exactly 14 elemental members. What are the precise starting and en — d and f Block Elements Chemistry Question

💡 Solution & Explanation

Lanthanum ($La, Z=57$) is formally a d-block element where the $5d$ orbital receives an electron. The filling of the $4f$ subshell strictly begins at Cerium ($Ce, Z=58$) and finishes when the shell is completely full at Lutetium ($Lu, Z=71$).