Atomic and Ionic Radii By, Emily Gitt, Greg Nicol, CJ Riutzel, Jordan Freeman

The atomic radii are the distance from the nucleus to the furthest stable electron orbital. Atomic radii is used to determine the average length of the bond between two atoms. The increasing of the shell and increasing nuclear charge explains why the radii decreases from left to right on the periodic table. There are less electrons in the valence shell on the left and as you move to the right the number of electrons increases which causes the atom to be smaller because the electrons pulled in with a large force because of the greater attraction between the electrons and the nucleus. The columns will increase as you move down. The orbital get larger as you work your way down the table as the atomic numbers increase as well.

Along a period, atoms gain electrons while remaining in the same valence shell. As electrons are added to a valence shell, the effective nuclear charge of that atom increases. Due to the increase in effective charge, the electrons are pulled closer to the nucleus, decreasing the atomic and ionic radii.

The relationship between the atoms in the periodic table has everything to do with effective nuclear charge. Below is a scatter plot which shows the radius in relation to the atomic number. The reason that the atoms with the valence electrons in the S sub-level are larger than any of the others is that the electrons do not feel a very strong pull, because the effective nuclear charge is small. As you move to the higher levels, as explained before, the effective nuclear charge increases, and the electrons pull in closer, creating a smaller atom, and a smaller radius.

The trends in the atomic radius in the periodic table form a pattern, but it depends on which measure of atomic radii you use. When metallic radii and covalent radii are combined they form a covalent bond. The measure of atomic radius is called the van der Waals, also know as unsquashed. At the end of the periodic table you have to ignore the noble gas because neon and argon dont form a bond therefore, you can only measure their van der Waals.