Question

Why does fluorine have a smaller atomic radius than carbon?

Answer 1

In general, the atomic radius decrease as we move from left to right in a period in the periodic table. As we move along period the magnitude of nuclear charge increases while the corresponding addition of electron take place in the same principle shell. As a result, electrons are pulled closer to the nucleus by the increased effective nuclear charge and thereby, cause a decrease in the size of the atom. In this way, the atomic radii of fluorine is smaller than that of carbon.