You will need
  • Periodic table of elements
The first thing at hand must be a regular periodic table, in which in order to place all known to humankind chemical elements. To find this table very easily in any Handbook of chemistry, school textbook, or it can be purchased separately, in the nearest bookstore.
In the upper right corner of each of the chemical elements listed by its serial number. This number coincides with the atomic radius of this atom.
For example, the sequence number of chlorine (Cl) is 17. This means that the distance from the nucleus of an atom of chlorine to its farthest orbit the stable motion of the electron is equal to 17 PM. If you want to find not only the atomic radius but also the distribution of electrons in the electronic orbits, the data can be emphasized from the column of numbers located to the right of the name of a chemical element.