General Chemistry/Periodicity and Electron Configurations Blocks
of the Periodic Table  The Periodic Table does more than just
list the elements. The word periodic means that in each row, or
period, there is a pattern of characteristics in the elements.
This is because the elements are listed in part by their
electron configuration. The Alkali metals and Alkaline earth
metals have one and two valence electrons (electrons in the
outer shell) respectively. These elements lose electrons to form
bonds easily, and are thus very reactive. These elements are the
s-block of the periodic table. The p-block, on the right,
contains common non-metals such as chlorine and helium. The
noble gases, in the column on the right, almost never react,
since they have eight valence electrons, which makes it very
stable. The halogens, directly to the left of the noble gases,
readily gain electrons and react with metals. The s and p blocks
make up the main-group elements, also known as representative
elements. The d-block, which is