The chemistry of the actinoid elements is not so smooth as that of the lanthanoid. Justify this statement by giving some example from the oxidation state of these elements

Explanation

Lanthanoids shw limited number of oxidation state e.g., `+2+3` and `+4` (out of which `+3` is most common). This is because of large energy gap between `4f,5d` and `6s` subshells. The dominant state of actinoids is also `+3` but they show a number of other oxidation states also,
e.g., uranium `(Z=92)` and plutonium `(Z=94)`, Show `+3`,`+4,+5` and `+6`, neptunium `(Z=94)` shows `+3,+4,+5` and `+7`, etc. This is due to small energy difference between 5f, 6d and 7s subshells of the actinoids.