JEE MainChemistryd and f Block Elements
Europium (II) exhibits a highly stable half-filled 4f⁷ electronic configuration. Which of the following statements correctly describes its preferred chemical behavior in aqueous solutions?
Options
- AIt prefers to gain an electron and acts as a strong oxidizing agent.
- BIt prefers to lose an electron to reach the +3 state, acting as a strong reducing agent.
- CIt remains completely inert and does not undergo any redox reactions due to its stable half-filled core.
- DIt undergoes rapid disproportionation to form elemental europium and europium (III) ions.
Correct answer
B. It prefers to lose an electron to reach the +3 state, acting as a strong reducing agent.
Step-by-step solution
Although Europium (II) has a stable half-filled 4f⁷ electronic configuration, the most characteristic and thermodynamically stable oxidation state for all lanthanoids in aqueous solutions is +3 . To achieve this most stable +3 state, Eu ²⁺ readily loses one electron to become Eu ³⁺ . Since it undergoes oxidation (loss of an electron), it acts as a strong reducing agent. Answer: It prefers to lose an electron to reach the +3 state, acting as a strong reducing agent.