Question

If a Calcium atom with atomic number 20 and mass number 41 undergoes a ${\beta }^{-}$ (beta minus)
The value of Z is__ and A is___in the daughter nucleus.

• A. $A=31$, $Z=41$
• B. $A=21$, $Z=41$
• C. $A=22$, $Z=41$
• D. $A=21$, $Z=42$

Answer 1

The correct option is B $A=21$, $Z=41$

Since in beta minus a neutron converts into a proton so the atomic number has to increase by 1.
Will the mass number change??
Hmmm...
Not exactly right.
Now I have a neutron less but a proton more, so the mass number is gonna remain unchanged. This means the Z will be 21 and A will remain 41.