A neutral atom consits of a positively charged nucleus
surrounded by acloud of negatively charged electrons; the total
charge on the electrons is equal to that on the nucleus. If an
electron is removed from the atom, the atom is said to have been
oxidised. Of course, we may be able to continue to remove
electrons from the atom, and each step is a further oxidation.
Consider the copper (Cu) oxide, CuO. We may write that Cu2+ O2-,
to illustrate that two electrons have been removed from the Cu,
and given to the O to form the oxide. It was this kind of
process that eventually gave the name oxidation to electron
removal from an atom or a molecule. The atom or molecule
receiving the electron is said to have been reduced. Note that
the removal of an electron from a charged atom which has been
reduced, e.g. C1-, is also A free radical is an electron that is
not magnetically paired up with another electron. Electrons are
not only charged, they are magnetic as well because they possess
a spin, an angular momentum. Two