One
of the triumphs of quantum mechanics was the successful explanation
of the arrangement of electrons in atoms and the structure of the
periodic table. Now that we have seen (Chapter 8) how the table
is based on electronic structure, we can present an overview of
the chemical elements that make up our universe. This is the full
deck with which the game of chemistry is played. This chapter will
be a wrap-up of the ideas presented in the first nine chapters.
The rows or periods of different length in the table represent
the filling of different orbitals: s in Row 1; s + p
in Rows 2 and 3; s + d + p in Rows 4 and 5; and s + f
+ d + p in Rows 6 and 7. The fully developed table from Chapter
8 is shown in the right margin, with the representative elements
(filling of s and p orbitals), transition metals (d
orbitals), and inner transition metals (f orbitals) differentiated
by color. Each period begins with the occupancy of a new s
orbital and (after Row 1) ends with a noble gas with a closed s
+ p electron shell. The representative elements are divided
vertically into eight groups, labeled IA through VIIA, and
0 for the noble gases. The Roman numeral in the group number indicates
the number of s and p electrons in the outer shell.
Representative elements reflect the filling of
s and p orbitals, transition metals of f orbitals.
The extra-long form of the periodic table at the top shows the filling
of the orbitals in their proper order, but is large and clumsy. The
standard long form of the table below it removes the inner transition
metals to as separate block, and the short form shown on the previous
page also separates out the transition metals