As you move from row to row in the periodic table, the atomic radius of the elements decreases. a) 1 to 7 b) 1 to 18 c) 7 to 1 d) 18 to 1

C) 7 to 1

Explanation:

The periodic trend of Atomic Radii for the Periodic Table of Elements is down and to the left the atomic radii increases.

So, from period 1 to 7 and group 18 to group 1, the atomic radii increases.

The opposite (decreasing) would be from period 7 to 1 and group 1 to group 18.

Therefore, our answer is C.