Question

Common oxidation state of $f$ -block elements is $III$. The other stable oxidation states of ${}^{63}Eu$ and ${}^{65}Tb$ are respectively

• A. II, IV
• B. IV,II
• C. II, V
• D. V , I

Answer 1

Answer: (A)

Common oxidation state of $f$ - block elements is $(+)3$, but $Eu$ and $Tb$ can also show $(+)2$ and $(+)4$ oxidation states respectively because of $4f^7$ and $4f^9$ electrons in $4f$ -subshell respectively.