Answer:
A negative beta particle
Yes
Step-by-step explanation:
The incomplete equation of the reaction:
²⁰³₈₀Hg → ²⁰³₈₁Tl + ?
In order to balance nuclear equations, we must conserve the mass number and atomic number.
For the mass number; 203 = 203 + a
a = 0
Atomic number; 80 = 81 + b
b = -1
The unknown has no mass number but an atomic number of -1
This a negative beta particle and it is designated as ⁰₋₁e