Chemistry - PERIODIC TABLE Question with Solution | TestHub

${}_{89}\mathrm{Ac}{\to }_{103}\mathrm{Lr}$

Belongs to actinoids series and they all belongs to $3^{\mathrm{rd}}$ group. So atomic n o. $101$ element is actinoids and atomic number $104$ element belongs to $4^{\mathrm{th}}$ group.