d and f BLOCK ELEMENTS

When comparing atomic radii, what general trend is observed from the first (3d) to the second (4d) series?

• Decrease
• Remain the same
• Increase
• Fluctuate randomly

What is the primary cause of the Lanthanoid contraction?

• Effective shielding by 4f electrons
• Poor shielding effect of 4f electrons
• Decreasing nuclear charge
• High ionisation energies

What phenomenon explains why the atomic radii of the third (5d) series are similar to the second (4d) series?

• Actinoid contraction
• Lanthanoid contraction
• Poor shielding by 5d electrons
• Increased nuclear charge in 5d elements

What is the underlying reason for the decrease in ionic radius across a transition series, according to the provided text?

• Effective shielding by d electrons
• Poor shielding by d electrons combined with increasing nuclear charge
• Decreasing nuclear charge
• Adding electrons to outer shells

Which of the following best describes the change in ionic radius for ions with the same charge across a transition metal series?

• Progressive increase with increasing atomic number
• Remains constant
• Progressive decrease with increasing atomic number
• Fluctuates randomly