Answer: Actinides show greater variety of oxidation states (due to 5f, 6d and 7s close in energy) vs lanthanides (predominantly +3).
- A Actinides show greater variety of oxidation states (due to 5f, 6d and 7s close in energy) vs lanthanides (predominantly +3)
- B There is said to be essentially no meaningful chemical difference between the two series overall in most cases under typical conditions
- C Actinides are said to be largely non-radioactive elements, unlike the well-known lanthanides according to standard textbooks
- D Lanthanides are said to characteristically show a far wider range of oxidation states than actinides in general practice
Correct answer: A. Actinides show greater variety of oxidation states (due to 5f, 6d and 7s close in energy) vs lanthanides (predominantly +3)
Explanation: In lanthanides, 4f is much lower in energy than 5d and 6s; predominant state is +3. In actinides, 5f/6d/7s are close in energy, enabling multiple stable oxidation states (+2 to +7).
Aqueous solutions of transition metal ions show characteristic colours caused by electrons absorbing visible light to jump between split d-orbitals; the exact colour depends on the metal, its oxidation state, and surrounding ligands.
Concept context
Transition metals (d-block) and lanthanides/actinides (f-block). Known for coloured compounds, variable oxidation states, complex formation, and catalytic properties. Frequently tested in JEE and NEET.