Answer:
After a nucleus with 85 protons undergoes alpha decay, it has 83 protons.
Explanation:
In an alpha particle there are two protons
In the given substance's nucleus, there are total of 85 protons
After the decay, the proton number reduce
The current proton number after decay is
85 -2 = 83
After a nucleus with 85 protons undergoes alpha decay, it has 83 protons.
