Answer:
The atom gains one proton
Step-by-step explanation:
Basic definitions:
- The atomic number of an atom is the number of protons in the nucleus:
Z = p
where p is the number of protons
- The mass number of an atom is the number of protons + neutrons in the nucleus:
A = p + n
where p is the number of protons and n the number of neutrons
In this problem, both the atomic number and the mass number increases by one unit, so:
Z' = Z + 1
A' = A + 1
Re-writing the two equations in terms of p and n:
p' = p + 1 (1)
p' + n' = (p+n) + 1 (2)
From eq.(1), we see that the number of protons has increased by one unit. Substituting p' from eq.(1) into eq.(2),
(p+1) + n' = (p+n) + 1
p + 1 + n' = p + n +1
--> n' = n
which means that the number of neutrons has not changed.