NEETChemistryd and f Block Elements
Which of the following statements regarding the f-block elements is incorrect?
Options
- AActinoid contraction from element to element is greater than lanthanoid contraction due to poorer shielding by
- BActinoids exhibit a larger number of oxidation states because of the very small energy gap between 5f , 6d and
- CBoth lanthanoids and actinoids display +3 as the most common oxidation state.
- DThe first ionization enthalpies of early actinoids are higher than those of the corresponding early lanthanoid
Correct answer
D. The first ionization enthalpies of early actinoids are higher than those of the corresponding early lanthanoid
Step-by-step solution
The first ionization enthalpies of early actinoids are actually lower than those of the early lanthanoids. This is because 5f electrons penetrate less into the inner core and are less tightly bound by the nucleus compared to 4f electrons, making them easier to remove. The other statements are correct facts regarding f-block elements. Actinoid contraction is greater due to the poorer shielding effect of 5f electrons compared to 4f electrons. The small energy gap between 5f , 6d , and 7s allows actinoids to show a wi