Final answer:
To order the elements S, F, K, Cl, and Na by increasing atomic radius, apply the periodic table trends: atomic radius increases down a group and decreases across a period. The correct order is F, Cl, S, Na, K, with F being the smallest and K the largest.
Step-by-step explanation:
When arranging elements in order of increasing atomic radius, we must consider the arrangement of elements in the periodic table. Atomic radius tends to increase as you move down a group as the number of electron shells increases. Conversely, atomic radius decreases as you move from left to right across a period because the increased number of protons creates a greater positive charge, pulling the electrons closer. Based on these trends, the correct order of elements from smallest to largest atomic radius would be F, Cl, S, Na, K.
- Fluorine (F) has the smallest atomic radius due to its high electronegativity and its position at the top of the halogens group.
- Chlorine (Cl) has a larger radius than fluorine, being lower in the same group.
- Sulfur (S) comes next, being below chlorine in the periodic table and having an additional electron shell.
- Sodium (Na) has a larger radius than sulfur, lying further down on the periodic table.
- Potassium (K) has the largest radius of the group, being in the same group as sodium but in the next period down.