d and f BLOCK ELEMENTS

What effect does the filling of 3d orbitals have on the shielding of 4s electrons in the 3d series?

• 3d electrons provide worse shielding for 4s electrons
• 3d electrons provide better shielding for 4s electrons than electrons in the same outer shell
• 3d electrons have no effect on 4s electrons
• 3d electrons completely shield 4s electrons from the nuclear charge

What is the relationship between the number of unpaired d-electrons and the enthalpy of atomisation in transition metals?

• There is an inverse correlation; more unpaired electrons lead to lower enthalpies of atomisation
• There is no correlation
• There is a direct correlation; more unpaired electrons generally lead to higher enthalpies of atomisation
• The relationship depends on the specific element

Why is the first ionisation enthalpy of transition elements generally lower than that of the following group elements in the periodic table?

• Transition elements have fewer electrons
• The ns electrons are farther from the nucleus and less tightly held than the np electrons of the next group
• Transition elements have larger atomic radii
• The nuclear charge is lower in transition elements

What causes the break in the trend of steadily increasing second and third ionisation enthalpies in the 3d series?

• Decrease in atomic radius
• Formation of ions with particularly stable d5 configurations
• Increase in nuclear charge
• Decrease in shielding effect

Why do successive ionisation enthalpies for transition elements increase, but not as steeply as in non-transition elements?

• Transition elements have fewer protons
• Electrons in the same shell shield each other more effectively than electrons in different shells
• The nuclear charge decreases
• Transition elements have larger atomic radii