Final answer:
Zirconium (Zr) has no unpaired electrons in its atom.
Step-by-step explanation:
Zirconium (Zr) has the electron configuration [Kr]5s²4d². To determine the number of unpaired electrons, we look at the electron configuration in the outermost energy level, which is the 4d sublevel in this case. The 4d sublevel can hold a maximum of 10 electrons, and since there are only 2 electrons in the 4d sublevel of a zirconium atom, there are no unpaired electrons in an atom of zirconium (Zr).
In this subshell, there are two electrons present, and they occupy the 4d orbital. Since there are two electrons in the 4d orbital, and each orbital can hold a maximum of two electrons, we can conclude that there are no unpaired electrons in an atom of zirconium.