arrange the elements in order of increasing atomic radius. use the periodic table to help you. mg ba f s

Explanation:

Step1: Recall atomic - radius trends

Atomic radius decreases across a period and increases down a group in the periodic table.

Step2: Locate the elements

Fluorine (F) is in period 2, group 17. Sulfur (S) is in period 3, group 16. Magnesium (Mg) is in period 3, group 2. Barium (Ba) is in period 6, group 2.

Step3: Compare F and S

Since F is in period 2 and S is in period 3, F < S as atomic radius increases down a group.

Step4: Compare S and Mg

In period 3, atomic radius decreases from left - to - right. Mg is to the left of S, so S < Mg.

Step5: Compare Mg and Ba

Since Ba is in period 6 and Mg is in period 3, Mg < Ba as atomic radius increases down a group.

Answer:

F < S < Mg < Ba