How many valence electrons does iron have?
Iron has 8 valence electrons.
This is tricky!
You need to have a firm grasp of what you are talking about when you use the term "valence electrons."
For main-group elements, valence electrons are the electrons in the outermost shell of the atom.
But iron is a transition metal.
Transition metals can use the electrons in their
Thus, valence electrons for a transition metal are defined as electrons that reside outside a noble-gas core.
For example, silicon (a main-group element) has the electron configuration
Look at the numbers (not the superscripts) first!
The outermost shell is the third shell (
O.K. Now we can look at the superscripts (which designate the number of electrons in each orbital).
The total number of electrons in the
With me so far?
O.K., so let's answer your question!
Iron has an electron configuration
The electrons outside the noble gas core are?
Iron thus has 8 valence electrons!
Easy-Peasy, once you know the trick!
Note: Just because iron has 8 valence electrons doesn't mean that it will use them all.
Iron usually uses only two or three of its valence electrons to form compounds