Question

Gradual decrease in atomic and ionic radii from $C{e}^{3+}$ to $L{u}^{3+}$ is called

• A. Actinide contraction
• B. Lanthanide contraction
• C. Both (A) and (B)
• D. None of these

Answer 1

The correct option is B Lanthanide contraction

Lanthanide contraction is the gradual decrease in atomic and ionic radii from $C{e}^{3+}$ to $L{u}^{3+}$. As the electron falls into 5f orbitals the ENC (Effective Nuclear Charge) increases and this brings valence shell nearer to the nucleus resulting in lanthanide contraction.