Everything that we have learned in the preceding three chapters about the properties of elements applies to the heavier atoms, with one key difference:

The atoms of the third row are larger, so their outer electrons are further from the nucleus.

The diagram on the previous page shows the relative sizes of atoms when they are involved in metallic or covalent bonds. We saw these radii for the first ten elements in Chapter 3.

The ionic radii given in the diagram represents the sizes of ions having the closed-shell configuration of the nearest noble gas, positive ions for metals and negative ions for nonmetals.

These radii are the sizes of ions in salts.