d and f BLOCK ELEMENTS

Why do actinoid elements generally have even more complex chemistry than lanthanoids?

• Because they are radioactive.
• Because the 5f orbitals are less buried and more involved in bonding compared to 4f orbitals, and actinoids exhibit a wider range of accessible oxidation states.
• Because they were discovered later.
• Because they have higher atomic numbers.

What is the primary reason for the formation of complex ions by transition metals?

• Because they are cations.
• Because they are metals.
• Due to the presence of partially filled d-orbitals that can accept electron pairs from ligands, forming coordinate covalent bonds.
• Because they have high charges.

Why are interstitial compounds formed by transition metals?

• Because they are reactive.
• Because they have high melting points.
• Because the small size of non-metal atoms (like H, B, C, N) allows them to fit into the interstices (holes) within the close-packed metal lattice.
• Because they form ionic bonds.

Why do transition metal compounds often act as catalysts?

• Because they are metals.
• Because they are stable.
• Because transition metals can adopt multiple oxidation states and have partially filled d-orbitals that can form temporary bonds with reactants, providing an alternative reaction pathway.
• Because they are expensive.

Why do transition metals generally have high melting and boiling points compared to s-block metals?

• Because they are denser.
• Because they form strong metallic bonds involving the delocalization of both ns and (n-1)d electrons, creating a strong electrostatic attraction.
• Because they are harder.
• Because they have higher atomic numbers.