Atoms with the largest atomic radius can be found toward the bottom left corner of the periodic table. As you move down a group (vertical column), the atomic radius increases due to the addition of electron shells. Simultaneously, as you move from right to left across a period (horizontal row), the atomic radius also tends to increase because the effective nuclear charge felt by the electrons decreases, allowing the outer electrons to be held less tightly.
Therefore, the largest atomic radius is typically found in the alkali metals (group 1) at the bottom of the periodic table, with cesium (Cs) being one of the elements with the largest atomic radius.