Question

Calculate the number of protons, neutrons and electrons in ${}^{80}35\text{Br.}$

Answer 1

The composition of an atom can be represented as ${}_Z^{A}X$
where $X$ represents the symbol of the element, $Z$ denotes the atomic number and $A$ represents the mass number.
For a neutral atom,
(i) Atomic number $\left(Z\right)$ = number protons in the nucleus of an atom
= number of electrons in a neutral atom.
(ii) Mass number $\left(A\right)$ = number of protons $\left(Z\right)$ + number of neutrons $\left(n\right)$

Calculation of number of protons and electrons

For ${}^{80}35\text{Br},Z=35\text{and}A=80$
As it is a neutral species, so
number of protons = number of electrons $=z=35$
Calculation of number of neutrons
We know,
Mass number $\left(A\right)$ = number of protons $\left(Z\right)$ + number of neutrons $\left(n\right)$
So, number of neutrons $=A-Z$
$=80-35=45$
Final Answer: $p=35,e^{-}=35,n=45$