Atomic Radius

Question 1

What is atomic radius?

Answer 1

Distance from center of nucleus to outermost electron

Question 2

Why does atomic radius decrease across a period?

Answer 2

Increasing number of protons increases nuclear pull while electrons remain in the same energy level, pulling them closer to the nucleus.

Question 3

Why does atomic radius increase down a group?

Answer 3

Additional energy levels increase shielding and distance from the nucleus, making the atom larger.