Actinoid contraction is greater from element to element than lanthanoid contraction. Why?

The lanthanoid contraction relates to

(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.

In What way, the electronic configuration of the transition elements is different from that of the non-transition elements ?

Because of lanthanoid contraction, which of the following pairs of elements have nearly same atomic, radii? (Numbers in the parenthesis areratomic numbers).

Why do actinoids in general exhibit a greater range of oxidation states than the lanthanoids?

Hydrogen is the lightest element but helium has lowest boiling point why ?

What are zero group elements ? Give the electronic configuration of the first four of them. Why zero group elements are also known as inert gases ?

Define lanthanoid contraction. Write two consequences of it.