d and f BLOCK ELEMENTS

What is the primary source of electrons for metallic bonding in transition elements?

• Only the ns electrons
• Both the ns and (n-1)d electrons contribute significantly
• Only the (n-1)d electrons
• Electrons from the (n-2) shell

Why do the ionisation enthalpies of transition elements not increase as steeply as those of non-transition elements across a period?

• Transition elements have lower nuclear charges
• The inner d electrons shield the outer s electrons more effectively than electrons in the same shell
• The atomic radii of transition elements are larger
• Transition elements lose electrons more easily

What is the reason for the small irregularities observed in the first ionisation enthalpy trend of 3d transition metals?

• Large changes in atomic radius
• Small changes in the relative energies of 4s and 3d orbitals upon electron removal
• Variations in nuclear charge
• Differences in electron shielding

Why do transition metals generally have higher densities than s-block metals?

• They have larger atomic radii
• They have higher atomic masses and smaller atomic radii compared to s-block metals
• They form ionic compounds
• They have lower atomic masses

What is the effect of forming a d5 ion on the ionisation enthalpy trend?

• It causes a spike in the ionisation enthalpy
• It causes a break or dip in the expected increasing trend of ionisation enthalpy
• It has no effect on the trend
• It makes the trend perfectly linear