How many unpaired electrons are in the orbital diagram for each of the following elements?
Thallium
Calcium
Zirconium
Thallium: Thallium has an atomic number of 81. In the orbital diagram, it is filled up to the 5s orbital. The remaining electrons occupy the 4d orbitals. Since the 4d orbitals can hold up to 10 electrons, there are 10 electrons in the 4d orbitals for Thallium. Therefore, Thallium has 1 unpaired electron.
Calcium: Calcium has an atomic number of 20. In the orbital diagram, it is filled up to the 4s orbital. Therefore, all the electrons in Calcium are paired up and there are no unpaired electrons.
Zirconium: Zirconium has an atomic number of 40. In the orbital diagram, it is filled up to the 5s^2 4d^2 orbitals. Totaling to 4 electrons. Therefore, Zirconium has 4 unpaired electrons.