Which of the following statements is incorrect about the `f-` block elements ?

Options

A. `f-` block consists of two series, lanthanoids and actinoids.
B. Lanthanoids shown in general stable common oxidation state, `+3`
C. The actinoids are radioactive elements.
D. Actinoids contractions is smaller from element to element then lanthanoid contraction.

Answer

4

Explanation

In addition to 4f electrons, the 5f electrons themselves provide poor shielding from element to element in the series so, actionoid contraction is greater than lanthanoid contraction.