AtomicRadius Samples on Atomic Radius

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Atomic Radius

Atomic radius is simply the radius of the atom, an indication of the atom's volume.

Period - atomic radius decreases as you go from left to right across a period.

Why? As you move from left to right, the number of positive charges within the nucleus increases and hence increase the force of attraction between protons and electrons based on the relationship, F= KQQ/R^2. The stronger the attraction force, the smaller the radii. Therefore, atomic radii decrease as you move across the periodic table from left to right

Group - atomic radius increases as you go down a group.

Why? As you move from period to period down a group, new energy levels of elections clouds are added and hence weaken the force of attraction between the electron and protons. This is called "sheilding effect."