(i) Which orbitals are filled with electrons in 3rd period?
(ii) Which of the lanthanoids is man-made element?
(iii) To which series do man-made elements belong?
(i) In third period, 3s and 3p orbitals are filled.
(ii) Promethium (Pm) with atomic number 61 is a man-made lanthanoid.
(iii) Actinoid series (f-block elements).