How does atomic radius change from left to right across a period in the periodic table?

1 Answer
Oct 26, 2015

The trend in the periodic table is from right to left, and top to bottom, the atomic radii increases.


Top to bottom: because as you go down the periodic table, the energy level increases, the electrons (which is negatively charged) orbits further away from the positive nucleus, which means the attraction between the two is weak making the radius bigger.

Right to left: because basically, the element in the left is in the same energy level as with the element in the right but since there are more electrons (and protons) on the elements on the right, the magnetic attraction between them is stronger compared to the element on the left which has fewer number of electrons and protons.