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

The cause of variable oxidation state among transition elements is

The halides of transition elements become more covalent with increasing oxidation state of the metal. Why ?

Compare the chemistry of actinoids with that of the lanthanoids with reference to (i) electronic configuration (ii) oxidation state (iii) chemical reactivity

With which element oxygen shows positive oxidation state in its compounds :

(i) Which is the last element in the series of the actinoids? Write the electronic configuration of this element. Comment on the possible oxidation state of this element. (ii) What is lanthanoid contraction? Name an important alloy which contains some of the lanthanoid metals.

The element which forms oxides in all oxidation states from +1 to +5