Name the elements which have the smallest and the largest atom?

Keep in mind these two tendencies when forecasting how the atomic radius will vary as you proceed through the periodic table.
1. In a certain group, the atomic radius of the atoms will grow as you proceed down the table.
2. The atomic radius will decrease in a particular period as you go from left to right.
The atom with the lowest radius is helium. The periodic table trends and the effective nuclear charge, which keeps the valence electrons in close proximity to the nucleus, are to blame for this. Atomic radius decreases as you move up a group from bottom to top and across a period from left to right. The table's upper right corner, where He is located, must have the smallest atomic radius.
As a result, it is discovered that Francium is the greatest element and that Helium is the smallest element.