Answer:
Na> Mg > Si > P > Ar (option D)
Explanation:
Step 1: Data given
The radius of atoms increases as you go down a certain group.
The size of an atom will decrease as you move from left to the right of a period
All the elements are in the same period (period 3). This means The element the most on the left has the biggest size. The more to the right the smaller it gets.
Sodium (Na) is the element most on the left ( in group 1). Sodium has the biggest radius.
Magnesium is in group 2. This element has the second biggest radius.
Silicon is in group 14. This element has the third biggest radius.
Phosphorus is in group 15. This element has a smaller radius than Silicon.
Argon is the most on the right in period 3, so it has the smallest radius of all these elements.
Na> Mg > Si > P > Ar
