d and f BLOCK ELEMENTS

What is a notable characteristic feature of transition elements regarding their oxidation states?

• They show a great variety of oxidation states in their compounds
• They only show a single oxidation state
• They show oxidation states only in the +2 and +3 range
• They show fewer oxidation states than main group elements

Which of the following best describes the relationship between ionization enthalpies and the stability of oxidation states in transition elements?

• Ionization enthalpies provide some guidance, but the stability of oxidation states is a complex issue
• Ionization enthalpies are the sole determinant of oxidation state stability
• Higher ionization enthalpies always lead to more stable oxidation states
• Lower ionization enthalpies always lead to less stable oxidation states

What is the lowest common oxidation state exhibited by the first-row transition elements?

• +2
• +1
• +3
• +4

Why is it generally difficult to achieve oxidation states higher than +2 for elements like Copper, Nickel, and Zinc?

• Their high third ionization enthalpies make further ionization energetically unfavorable
• They lack available 4p orbitals
• They have very high electronegativity
• Their atomic radii are too small

What factor contributes most to the high third ionization enthalpies observed for d5 and d10 ions like Mn2+ and Zn2+?

• The inherent stability of the half-filled (d5) and completely filled (d10) d subshells
• The large size of these ions
• The low nuclear charge of the parent atoms
• The presence of 4s electrons