posted by Danielle on .
Which of the following atoms is paramagnetic?
Zn, Sr, Kr, Te, Ca?
How do you tell if the atom is paramagnetic or not?
If it has unpaired electrons it is paramagnetic. For example,
Zn is atomic number 30. Electrons are
1s2 2s2 2p6 3s2 3p6 3d10 4s2
No unpaired electrons
Co^+2 Co is atomic number 27.
1s2 2s2 2p6 3s2 3p6 3d7
All electrons are paired in 1s2 2s2 2p6 3s2 and 3p6 since all of those orbitals are full. How about the 3d7? d orbitals can hole 10 electrons. Remember Hund's rule that electrons don't pair until forced; therefore, that would allow the 5 d electrons before pairing starts and two pair so there are 3 unpaired electrons.