d and f BLOCK ELEMENTS

Why might the chemistry of elements succeeding actinoids be less known?

• They are all noble gases.
• They are naturally abundant and stable.
• Their synthetic nature and short half-lives make study difficult.
• They only exist in outer space.

What is the main implication of the text regarding the early members of the actinoid series?

• They are chemically inert.
• They have higher melting points.
• They have lower ionization enthalpies and higher reactivity.
• They behave exactly like lanthanoids.

Which statement best summarizes the comparison of lanthanoid and actinoid contractions' importance?

• Actinoid contraction is always larger.
• Lanthanoid contraction is more important due to better-known chemistry of subsequent elements.
• Both are equally important.
• Actinoid contraction only affects actinoids.

What does the text imply about the availability of 5f electrons for bonding in actinoids compared to 4f electrons in lanthanoids?

• 4f electrons are more available for bonding.
• 5f electrons are more available for bonding.
• Both are equally available.
• Neither is available for bonding.

According to the text, how does the reactivity of bulk actinoid metals compare to when they are finely divided?

• Bulk metals are completely inert.
• Bulk metals are just as reactive.
• Bulk metals are still significantly reactive, but less so than finely divided.
• Finely divided metals are less reactive.