Question

which atom has the largest atomic radius? cesium potassium francium rubidium

Explanation:

Step1: Recall atomic radius trend

Atomic radius increases down a group (column) in the periodic table.

Step2: Identify group of elements

Cesium (Cs), Potassium (K), Francium (Fr), Rubidium (Rb) are all in Group 1 (alkali metals).

Step3: Determine position down group

The order from top to bottom in Group 1 is: K, Rb, Cs, Fr. Francium is the lowest in the group.

Step4: Conclude largest radius

Since atomic radius increases down the group, Francium has the largest atomic radius.

Answer:

francium