d and f BLOCK ELEMENTS

Why is the third ionization energy of Iron (Fe) significantly higher than its first two?

• It removes a core electron.
• The 3d electron is closer to the nucleus.
• It involves removing an electron from the stable half-filled 3d subshell.
• The nuclear charge increases significantly.

What is the primary factor determining the preferred geometry of a transition metal complex?

• The number of ligands only
• The size of the metal ion only
• The nature of the metal ion and the ligands, particularly the ligand field stabilization energy.
• The temperature of the reaction.

Why do the atomic radii of transition metals within a period initially decrease and then remain relatively constant?

• d-electrons increase the atomic size.
• Electrons are only added to the s-subshell.
• The initial decrease is due to increasing nuclear charge, while the later constancy is due to shielding by d-electrons.
• Ionization energy trends cause this.

What is the relationship between the number of unpaired electrons and the magnetic moment of a transition metal complex?

• Fewer unpaired electrons lead to a higher magnetic moment.
• There is no relationship.
• More unpaired electrons generally lead to a higher magnetic moment.
• Paired electrons contribute most to the magnetic moment.

Why is the +2 state of Copper (Cu) less stable compared to its +1 state in aqueous solution?

• The +2 state has lower charge density.
• The +1 state (Cu⁺) has a fully filled 3d subshell, providing extra stability.
• The +2 state is harder to oxidize.
• The +1 state is larger.