Question

The incorrect statement among the following is :

• A. Actinoid contraction is greater for element to element than Lanthanoid contraction.
• B. Most of the trivalent Lanthanoid ions are colorless in the solid state.
• C. Lanthanoids are good conductors of heat and electricity.
• D. Actinoids are highly reactive metals, especially when finely divided

Answer 1

Answer: (B)

Most of the trivalent Lanthanoid ions are colorless in the solid state.

Answer 2

Most of Lanthanoids in trivalent state are coloured
due to unpaired electrons in $f$ - subshell. $La^{+3}, Lu^{+3}$ are
colourless