Question

Which of the following actinoids exhibits only + 3 oxidation state?

Options

• Lr (Z = 103)

• U (Z = 92)

• Th (Z = 90)

• Pa (Z = 91)

Answer 1

Lr (Z = 103)

Explanation:

Only the + 3 oxidation state is seen in Lawrencium (Lr), which has the electronic structure [Rn] 5f¹⁴7s²7p¹. To produce a stable +3 oxidation state, this element can easily give up three valence electrons from the 7s and 7p subshells. Because Lr has a fully filled (5f¹⁴) f-subshell, the state is particularly stable.