posted by Anonymous on .
Iron and manesiu are two common elements found in numerous compounds. magnesium is always in the +2 oxidation state while iron exhibits oxidation states of +2, +3,+4,and +6. why would magnesium not be found in the these upper oxidation states.
Think about the electron configuration.
12 Mg 1s2 2s2 2p6 3s2
26 Fe 1s2 2s2 2p6 3s2 3p6 3d6 4s2
You can see that if Mg loses two electrons it is left with a filled shell of 8 electrons in N=2.
Fe, on the other hand, can lose two electrons from 4s2 and have 6 electrons remaining in the third shell, all with approximately the same energy as the 4s electrons; therefore, Fe is more likely to exhibit numerous oxidation states as well as the +2 state.