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.