Ask A Scientist© Chemistry Archive

name         Lisa
status       student
age          13
Question -   Please explain to me what Fe3+ or Fe2+ is.
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Hi Lisa!
First dear, we are not allowed to answer directly to the sender or to
anybody but NEWTON, that is the owner of this list and organizes
questions and answers that way.
Elements atoms are neutral, that means they have  the number of positive
charges (protons) = number of negative charges (electrons).
But they can turn into ions, by loosing, or gaining electrons.
If they loose the number of positive charges becomes bigger than
the number of negative ones, and instead of beeing neutral the atom
become positively charged, and is called cation. So when
you mention Fe+3  that means one iron cation (ferric) with charge +3,
having loose 3 electrons. The same way, Fe+2 (ferrous) has a +2
charge and the neutral atom lost 2 electrons.
And thanks for asking NEWTON!
Mabel
(Dr Mabel Rodrigues)
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Iron, Fe, can exist in several "oxidation states" that is the number of
[fewer] electrons under the influence of the atom. Every element is assigned
an "oxidation state" of zero. If the atom has a deficiency of say 2
electrons, as in the case of Fe+2 that species is named the ferrous ion. In
the event there is a deficiency of three electrons in iron, Fe+3, the
species is named the ferric ion. The value of the oxidation state is
important because it gives a clue as to how many ions of the opposite charge
it takes to form stable compounds. In the case of [Fe+2] the chloride FeCl2
forms, because the "oxidation state" of Cl ion is [Cl-1]. In the case of
[Fe+3] the common salt would have the formula FeCl3.

Vince Calder
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Lisa-
      Iron, Fe, is an element. atoms are electrically neutral, meaning they
have equal numbers of positive charges (protons) and negative charges
(electrons). When an atom gains or loses negative charge (electrons) the
atoms become ions. When an atom loses electrons, there are then more
positives than negatives, so the atoms becomes a positive ion. That is what
has happened to Fe+2  (lost 2 electrons) and Fe+3 (lost 3 electrons ) .
Metals, by definition, are substances that tend to lose electrons. Nonmetals
tend to gain electron. If you have a science book handy I'd look up, ions,
and oxidation and reduction reactions. Good luck!

Bob Blaus
York High School
Elmhurst, IL
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These are two oxidation states of iron.  Fe3+ is an iron atom missing three
electrons, and Fe2+ is an iron atom missing two electrons.  Because of the
missing electrons, the atoms have an overall positive electric charge.

Richard E. Barrans Jr., Ph.D.
Assistant Director
PG Research Foundation, Darien, Illinois
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