Question

A nucleus ${}_{11}^{24}\text{Na}$ is $\beta$-radioactive
a) What are the number 24 and 11 called?
b) Write the equation representing $\beta$ - decay.
c) What general name is given to the product nucleus with respect to ${}_{11}^{24}\text{Na}$ ?

Answer 1

(a) Atomic number $Z$ and mass number $A$ of nuclei $X$ is represented by:
${}_Z^A\text{X}$
where Z = Atomic number,
A = Mass number
For the sodium atom ${}_{11}^{24}\text{Na}$
Atomic number, Z = 11
Mass number, A = 24

(b) When a beta particle is emmited atomic number $Z$ of the doughter nucleus increase by 1 but mass number $A$ remains the same
${}_{11}^{24}\text{Na}{\to }_{11}^{24}\text{Mg}+{}_{-1}^0\beta +energy$

(c) $\beta$ decay converts one neutron to one proton.
Thus the product is ${}_{11}^{24}\text{Mg}$, an isobar of ${}_{11}^{24}\text{Na}$.