d and f BLOCK ELEMENTS

What irregularity in electronic configuration is highlighted for Americium (Am) in the text?

• It has a completely filled 5f subshell
• It has no 5f electrons
• It has 7 electrons in its 5f subshell, relating to a potentially stable configuration
• Its 6d subshell is completely filled

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

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

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

• +3
• +4
• +5
• +6

In terms of compound formation, how do actinoids resemble lanthanoids?

• Both series exclusively form compounds in the +3 state
• Both series form more compounds in the +4 state
• Both series form an equal number of +3 and +4 compounds
• Both series form a greater number of compounds in the +3 oxidation state compared to the +4 state

How is the shielding effectiveness of 5f electrons described in the text?

• It is described as excellent
• It is described as moderate
• It is described as poor
• It is stated to be the same as the shielding by 4f electrons