Answer:
(a) Alkali metals: Francium (Fr)
(b) Chalcogens: Polonium (Po)
(c) Noble gases: Radon (Rn)
(d) Alkaline earth metals: Radium (Ra)
Explanation:
In the periodic table, the atomic mass increases down the group. Therefore, the last element of a group is the heaviest element of the group.
(a) alkali metals: The chemical elements that are present in group 1 of the periodic table, except hydrogen.
The heaviest member of this group is francium (Fr)
(b) chalcogens: The chemical elements that are present in group 16 of the periodic table
The heaviest member of this group is polonium (Po)
(c) noble gases: The chemical elements that are present in group 18 of the periodic table
The heaviest member of this group is radon (Rn)
(d) alkaline earth metals: The chemical elements that are present in group 2 of the periodic table.
The heaviest member of this group is radium (Ra)
