Question

Actinides

• A. are all synthetic elements
• B. include element 104
• C. have any short lived isotopes
• D. have variable valency

Answer 1

Answer: (D)

All actinides show different oxidation states such as $+2+3+4+5$ and $+7$. However, $+3$ oxidation state is most common among all the actinides. The wide range of oxidation states of actinides is attributed to the fact that the $5f,6d$ and $7s$ energy levels are of comparable energies. Therefore, all these three sub-shells can participate.