Answer: Osmium (OsO 4 ) and Ruthenium (RuO 4 ).
- A Osmium (OsO<sub>4</sub>) and Ruthenium (RuO<sub>4</sub>)
- B Iron, which is most stable in the +2 and +3 oxidation states
- C Manganese, whose highest common oxidation state is +7
- D Chromium, whose highest common oxidation state is +6
Correct answer: A. Osmium (OsO<sub>4</sub>) and Ruthenium (RuO<sub>4</sub>)
Explanation: Os and Ru can reach +8 in their tetroxides (OsO<sub>4</sub>, RuO<sub>4</sub>), the highest oxidation states among transition metals.
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.