Which of the following specific Actinoid elements are definitively known to exhibit the maximum theo — d and f Block Elements Chemistry Question

💡 Solution & Explanation

The early actinoids can utilize all their valence electrons. Neptunium ($Np$) and Plutonium ($Pu$) possess enough electrons in their $5f, 6d, 7s$ orbitals and sufficiently close energy levels to push to a $+7$ oxidation state. Thorium maxes out at $+4$, and Americium at $+6$.