Knowing that the chemistry of lanthanoids (Ln) is dominated by its `+3` oxidation state, which of the following statement is incorrect?
A. The ionic sizes of Ln (III) decreases in general with increasing atomic number
B. Ln (III) compounds are generally colourless
C. Ln (III) hydroxides are mainly basic in character
D. Because of the large size of the Ln(III) ions the bonding in its compounds is predominently ionic in character
