Oxidizing agents readily accept electrons and get reduced. Let's consider the common oxidation states of the given lanthanides:
La and Lu: These lanthanides predominantly exist in the +3 oxidation state and are not strong oxidizing agents.
Eu and Yb: These lanthanides exhibit +2 and +3 oxidation states. Eu2+ and Yb2+ are reducing agents (they tend to lose electrons and get oxidized).
Therefore, only Ce4+ and Tb4+ from the given options are good oxidizing agents.
List I | List II | ||
---|---|---|---|
A | Mesozoic Era | I | Lower invertebrates |
B | Proterozoic Era | II | Fish & Amphibia |
C | Cenozoic Era | III | Birds & Reptiles |
D | Paleozoic Era | IV | Mammals |