General Properties of Lanthanoids

Ionisation enthalpy values of lanthanoids are quite comparable to which of the following alkaline earth elements?

Write the general properties of lanthanoids.

Among $\mathrm{Ce}\left(4{\mathrm{f}}^{1}5{\mathrm{d}}^{1}6{\mathrm{s}}^2\right), Nd\left(4{\mathrm{f}}^{1}6{\mathrm{s}}^2\right), \mathrm{Eu}\left(4{\mathrm{f}}^{7}6{\mathrm{s}}^2\right)$ and $\mathrm{Dy}\left(4{\mathrm{f}}^{10}6{\mathrm{s}}^2\right)$, the elements having highest and lowest $3$rd ionisation energies, respectively are

Why do lanthanoid form coloured compound?

Which of the following ions show colour:

Which one of the following lanthanide ions does not exhibit paramagnetism?

Which one of the following lanthanide ions does not exhibit paramagnetism?

Which one of the following lanthanide ions does not exhibit paramagnetism?

Which of the following statements is incorrect?

Which statements among the following are correct?

I. $\mathrm{C}{\mathrm{e}}^{+4}$ is an oxidizing agent & colourless.

II. $\mathrm{L}{\mathrm{u}}^{3+}$ is colourless.

III. Actinoids exhibit a higher number of oxidation states than lanthanoids.

IV. All 3d elements give ${\mathrm{H}}_2$ with 1 M HCl.

Rare-earth elements are exhibited by

Select the correct statements regarding inner transition elements.

 In context of the lanthanoids, which of the following statement is not correct?

Cerium (Z = 58) is an important member of the lanthanoids. Which of the following statements about cerium is incorrect?