# How do you think the atomic radii will change as electrons are added to a shell?

Jan 23, 2016

I assume you describe a Periodic trend. As electrons are added to the valence shell, an extra proton (i.e fundamental, positively charged nuclear particle) is added to the element's nucleus. As electrons add and $Z$ the atomic number increases 1 by 1, nuclear charge WINS, and electronic radii contract. The result is the well-established CONTRACTION of atomic radii ACROSS a PERIOD.