Where are the elements with the largest atomic radii found on the periodic table?

The elements with the largest atomic radii are found in the bottom left corner of the periodic table. This is because atomic radius generally increases as you move down a group (column) and decreases as you move from left to right across a period (row).

As you descend the periodic table, additional electron shells are added to the atoms, which increases the distance between the nucleus and the outermost electrons, thus increasing the atomic radius. In the bottom left corner, we have elements like cesium and francium, which not only have more electron shells but also have weaker effective nuclear charge acting on those outer electrons, leading to larger atomic sizes.

In contrast, elements located at the top right corner typically have the smallest atomic radii because they have fewer electron shells and a higher effective nuclear charge, which pulls the electrons closer to the nucleus. The middle section contains transition metals, which have varying radii, but generally, they do not reach the large sizes seen in the bottom left corner. The top left corner also exhibits relatively small radii when compared to the bottom left.