Match List-I with List-II.
| List-I (Series) | List-II (Elements of the series) |
|---|---|
| (A) 4d series | (I) Ce to Lu |
| (B) 5d series | (II) Th to Lr |
| (C) Lanthanoids | (III) Y to Cd |
| (D) Actinoids | (IV) La and Hf to Hg |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → A-III, B-IV, C-I, D-II
The d-block has four series of transition metals, named after the d orbitals being filled (3d, 4d, 5d, 6d). The f-block has two series in which the 4f and 5f orbitals are filled.
(A) 4d series — This matches (III) Y to Cd. The 4d orbitals fill in period 5, from yttrium (Z = 39) to cadmium (Z = 48).
(B) 5d series — This matches (IV) La and Hf to Hg. Lanthanum starts the 5d series; then the 4f series comes in, and the 5d filling continues from hafnium to mercury.
(C) Lanthanoids — This matches (I) Ce to Lu. These are the 4f series, the fourteen elements that follow lanthanum.
(D) Actinoids — This matches (II) Th to Lr. These are the 5f series, the fourteen elements that follow actinium.
NCERT (2026-27 edition):
The d- and f-Block Elements – “There are mainly four series of the transition metals, 3d series (Sc to Zn), 4d series (Y to Cd), 5d series (La and Hf to Hg) and 6d series which has Ac and elements from Rf to Cn. The two series of the inner transition metals; 4f (Ce to Lu) and 5f (Th to Lr) are known as lanthanoids and actinoids respectively.”