The incorrect statement among the following is : (2021) (a) Lanthanoid...
Incorrect statement: (d) Most of the trivalent Lanthanoid ions are colorless in the solid-state.
Explanation:
The statement that is incorrect among the given options is (d) Most of the trivalent Lanthanoid ions are colorless in the solid-state. This statement is not true because most trivalent Lanthanoid ions exhibit characteristic colors in the solid-state.
Lanthanoids as conductors of heat and electricity:
Lanthanoids, also known as rare earth elements, are generally good conductors of heat and electricity. This is due to the presence of partially filled 4f orbitals, which allow for the movement of electrons. The f-orbitals have a high electron density, which contributes to their metallic properties.
Actinoids as highly reactive metals:
Actinoids, like Lanthanoids, are also metals. However, they are highly reactive, especially when finely divided. This reactivity is due to their large atomic size and the presence of partially filled 5f orbitals, which make them prone to chemical reactions.
Actinoid contraction:
Actinoid contraction refers to the decrease in atomic and ionic radii across the actinoid series. This contraction is greater than the Lanthanoid contraction, which refers to the decrease in atomic and ionic radii across the lanthanoid series.
Color of trivalent Lanthanoid ions:
Most trivalent Lanthanoid ions exhibit characteristic colors in the solid-state. The color arises due to the absorption of certain wavelengths of light by the partially filled 4f orbitals. Each Lanthanoid ion has a unique electronic configuration, leading to different energy level spacings and absorption properties, resulting in different colors.
Overall, the incorrect statement among the given options is (d) Most of the trivalent Lanthanoid ions are colorless in the solid-state.
The incorrect statement among the following is : (2021) (a) Lanthanoid...
Option c is correct option