Q. Knowing that the chemistry of lanthanoids (Ln) is dominated by its +3 oxidation state, which of the following statements is incorrect?
A) Because of the large size of the Ln (III) ions the bonding in its compounds is predominantly ionic in character.
B) The ionic sizes of Ln (III) decrease in general with increasing atomic number.
C) Ln (III) compounds are generally colourless.
D) Ln(III) hydroxide are mainly basic in character.
Explanation
(c)
The most common oxidation state of lanthanoid is +3. Lanthanoids in +3 oxidation state usually have unpaired electrons in $f$-subshell and impart characteristic colour in solid as well as in solution state due to $f - f$ transition.
(Except lanthanum and lutetium)
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.