Questions related to distinguishing dimagnetism and paramagnetism and when is there magnetic properties

If a transition metal ion has both paired and unpaired electrons, would it be considered as showcasing paramagnetism or dimagnetism? I know that Fe2+, which has an abbreviated electronic configuration of [Ar]3d6 shows paramagnetism even though 1 of the d-orbitals have paired electrons. How about a transition metal ion with 7 / 8 electrons in d orbitals? Do we determine paramagnetism / dimagnetism based on whether there is greater number of paired / unpaired electrons or if a transition metal ion has unpaired electrons, it must be paramagnetic? I was thinking that there are many other orbitals in Fe2+ like the 3s, 3p orbitals and all of which contain paired electrons, so won't that outweigh the unpaired electrons in 3d orbitals? 
Also, the teacher taught the idea paramagnetism and diamagnetism in the context of transition metals and said that transition metals show magnetic properties. Why don't other species show magnetic properties cause they can also have paired / unpaired electrons?





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> Do we determine paramagnetism / diamagnetism based on whether there is greater number of paired / unpaired electrons or if a transition metal ion has unpaired electrons, it must be paramagnetic?
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[HyperPhysics](http://hyperphysics.phy-astr.gsu.edu/hbase/solids/magpr.html) writes:


"*Diamagnetism is a property of all materials and opposes applied magnetic fields, but is very weak. Paramagnetism, when present, is stronger than diamagnetism...*


That means the diamagnetism from any paired electrons is almost negligible compared to the paramagnetism from any unpaired electrons present - even if it's just one unpaired electron. So, as long as there are unpaired electrons, the material will be *observed* to be paramagnetic.


Watch out with your $\ce{Fe^2+}$ example. You are right in saying it is a $\mathrm{d^6}$ ion, but the ligands attached to it will determine whether it is diamagnetic (the low-spin case, e.g. with $\ce{CN-}$ ligands) or paramagnetic (the high-spin case, e.g. with $\ce{H2O}$ ligands). This phenomenon is explained by [crystal field theory](http://chemwiki.ucdavis.edu/Inorganic_Chemistry/Crystal_Field_Theory/Crystal_Field_Theory).



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> Why don't other species show magnetic properties cause they can also have paired / unpaired electrons?
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All species do show magnetic properties. The most famous example is diatomic oxygen, which is paramagnetic because of its unpaired electrons. Water, which has all its electrons paired, can be shown to be diamagnetic (again, just search Google - there are even YouTube videos on it).


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