Fructose

EN Periodic Table
As stated before the electronegativity of an element is a function of its Atomic Structure. Because
the nucleus of a smaller atom is closer to the shared pair of electrons in a bond than that of a
larger atom, the nucleus of the smaller atom attracts the bonding electrons more strongly than
that of the larger atom.
So EN is inversely related to the size of an atom. That is as the size of an atom increases, the EN
decreases. As the size of an atom decreases, the EN increases.
So, in general, since the size of an atom will go up as we proceed down a column (Group) of
elements in the Periodic Table, the EN will go down as we go down a Periodic Table Group (Column).
Also, as we proceed to go up in atomic number across a Row (Period) in the Periodic Table, the size
of atoms generally decreases due to larger numbers of electrons in the outer shell being attracted
to the nucleus. Thus the atomic size will generally decrease and the EN will increase as we go left
to right across a Periodic Table Row (Period).
We have illustrated this for you in the picture below.
One important use of electronegativity is in determining an atom's oxidation number (O.N.) The
oxidation number is sometimes called the valence number of an atom. In Ionic Compounds we
have defined the valence number as the number of electrons that an atom of an element must
give up or accept to achieve an electron-full outer shell.
For covalent compounds, which share electrons, we need a slightly different definition of the
oxidation number. We use the electronegativity and some other atomic structure information to
calculate the oxidation number as follows:
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