Actinides :
(i) The elements in which the extra electron enters `5f`-orbitals of(`n- 2`)th main shell are known as actinides.
(ii) The man-made eleven elements `Np_(93) - Lr_(103)` are placed beyond uranium in the periodic table and are collectively called trans- uranic elements.
(iii) `Th`, `Pa` and `U` first three actinides are natural elements.
(a) `text(Electronic configuration)`:-
The general configuration of actinides may be given as `5f^(1- 14) 6d^(0/1) , 7s^2`.
Some properties of Actinides is given in Table.
(ii) The man-made eleven elements `Np_(93) - Lr_(103)` are placed beyond uranium in the periodic table and are collectively called trans- uranic elements.
(iii) `Th`, `Pa` and `U` first three actinides are natural elements.
(a) `text(Electronic configuration)`:-
The general configuration of actinides may be given as `5f^(1- 14) 6d^(0/1) , 7s^2`.
Some properties of Actinides is given in Table.