Answer : The mass number will be zero and the emitted particle have negative charge.
Beta minus decay : It is a type of decay process, in which a neutrons gets converted to proton, an electron and anti-neutrino.
The beta minus decay equation is represented as,
[tex]_Z^A\textrm{X}\rightarrow _{Z+1}^A\textrm{Y}+_{-1}^0e[/tex]
(A is the atomic mass number and Z is the atomic number)
During beta minus decay, the mass number of particle emitted from the nucleus will be zero.
The particle emitted from the nucleus during beta minus decay have negative charge.
Hence, the particle emitted from the nucleus during beta minus decay have zero mass number and have negative charged.