Answer:
Yttrium
Explanation:
If you somehow subtracted a proton from a Zirconium atom, it would become a Yttrium atom.
When the number of protons in an atom changes a new element is directly formed. The difference between one atom and the other is the based on the number of protons they contain.
Therefore, when Zirconium loses a proton, it changes to Yttrium which is the atom before Zirconium.
Such reactions as this are very common with nuclear reactions. During a nuclear reaction, the nucleus of an atom changes stability.
