d and f BLOCK ELEMENTS

Which element marks the completion of the 5f subshell in the actinoid series?

• Actinium (Ac)
• Protactinium (Pa)
• Uranium (U)
• Lawrencium (Lr)

What is the highest listed oxidation state for Thorium (Th) according to Table 4.11?

• +3
• +4
• +5
• +6

In which oxidation state do actinoids resemble lanthanoids by having more compounds?

• +2
• +3
• +4
• +5

Which statement best describes the shielding provided by 5f electrons?

• It is excellent
• It is moderate
• It is poor
• It is the same as 4f electrons

What is a consequence of the comparable energies of 5f, 6d, and 7s orbitals in actinoids?

• Increased stability
• Simpler chemistry
• Greater range of oxidation states
• Lower reactivity