Lets assume we have a 1 foot square bar of Iron. I realize that unpaired valence shell electrons in an atom of a substance like Iron, all with the same electron spin---either +1/2 or -1/2---are consistent within the same atom, as indicated from the aufbau principle and experiments. So for an Iron atoms 4 unpaired valence electrons, let's arbitrarily say the spin on each of these 4 electron in the one atom is +1/2. I know these 4 electrons, all spinning in the same direction in this one atom, add up and give this particular Iron atom a magnetic field. Question: Do all Iron atoms that are adjacent to this original atom mentioned above have 4 unpaired valence electrons with the same spin quantum number as this original iron atom OR does each iron atom form it's spin quantum # of these 4 unpaired valence electrons independently of one another? I assume in a magnetic domain of a small section of this Iron bar there would be Iron atoms all having their unpaired electrons with the same spin quantum number? This would give this particular domain the same magnetic field? Adjacent domains would have different spin quantum numbers, by chance, and for the entire material, and these would cancel out unless an outside magnet is applied. Correlary: Could a domain be considered to be made from only one atom OR is it considered to be made from 1000s of atoms? Thanks for any insight.