What are transuranic elements?

Name the members of the lanthanoid series which exhibit $+4$ oxidation state and those which exhibit $+2$ oxidation state. Try to correlate this type of behavior with the electronic configurations of these elements.

What is the general electronic configuration of lanthanoids?

The ion with $4f^7$ configuration is

Identify the correct decreasing order of atomic radii from the following.

Fill in the blanks given below:
$(i)$ Neptunium and Plutonium are obtained from ............ .
$(ii)$ Lanthanoid series and Actinoid series are known as ............ .
$(iii)$ The main energy level of an atom is called ............ .
$(iv)$ Elements that possess both metallic and non-metallic properties are called ............ .