Answer:
The correct answer is - option D. Ar, P, Si, Mg, Na
Step-by-step explanation:
The atomic radius of an atom can be defined as half of the distance of the nucleus of two atoms in a diatomic molecule which is represented by r. This can be measure by measuring the distance of the nuclei in a diatomic molecule and divide it by 2.
Argon (Ar) - 0.71 Å
Phosphorus (P) - 0.98 Å
Silicon (Si) - 1.11 Å
Magnesium (Mg) - 1.45 Å
Sodium (Na) - 1.9 Å
Atmic radii is decreses as moving from left to right across a period in periodic table.