Question

All isotopes of a particular element have the same atomic number. How then do the isotopes of a particular element differ?

Answer 1

Hint: By the term isotopes, we simply mean those substances which have the same number of electrons in the atom but different number of the protons in the nucleus. So, by using this you can easily answer the given statement accordingly.

Complete answer:
First of all, let’s discuss what isotopes are. By the term isotopes, we means those substances or the elements which has the same atomic number i.e. Z but different mass number i.e.A.
Mass number of an atom or the element represents the numbers of the protons and the neutrons present in an atom. For example:- suppose the mass number of calcium is 40 and the number of protons present in the calcium is 20. Then, the number of neutrons present in the calcium can be found as;
$\begin{align}
  & \Rightarrow no.\text{ }of\text{ }protons+\text{ }no.\text{ }of\text{ }neutrons\text{ }=\text{ }mass\text{ }number \\
 & \Rightarrow 20+p\text{ }=40 \\
 & \Rightarrow p\text{ }=\text{ }40-20 \\
 & \Rightarrow p\text{ }=20 \\
\end{align}$
On the other hand, the atomic number of an atom or the element represents the number of electrons present in an atom.
Now considering the statement as-
So, from the definition , we come to know that though all the isotopes of a particular element have the same atomic number but then we can differentiate isotopes of a particular element from each other through their mass number. Example:- $C_{6}^{12}$ and $C_{6}^{14}$ are the isotopes of the element carbon.

Note:
The substances or the elements which have the same mass number but different atomic numbers are known as the isobars. Example:-chlorine-37 and argon-37 are isobars.