Final answer:
Atomic radius increases down a group and decreases across a period in the periodic table.
Step-by-step explanation:
The atomic radius of an atom is a measure of the size of its atomic structure. It is typically defined as half the distance between the nuclei of two adjacent atoms in a solid. In general, atomic radius increases as you move down a group (or column) in the periodic table and decreases as you move across a period (or row) from left to right.
Based on their positions in the periodic table, we can arrange the given atoms in order of increasing atomic radius:
- Phosphorus (P)
- Sulfur (S)
- Aluminum (Al)
- Sodium (Na)