Question

Isotopes have the same atomic number but different atomic mass number.
State whether the given statement is true or false
A. True
B. False

Answer 1

Hint: The total number of protons present the atomic nucleus is called its atomic number and mass number is the total number of protons and neutrons present in the atomic nucleus. In isotopes the atomic number is same in the atoms of given element and the number of neutrons may be different

Complete step by step solution:
The atomic mass number speaks about the total number of protons and neutrons present in an atomic nucleus.
Isotopes are defined as the atoms of the same element having same atomic number (same number of protons) but different atomic mass number (different number of neutrons)

Consider the example of Carbon isotopes
$_{\text{6}}{{\text{C}}^{{\text{11}}}}{{\text{,}}_{\text{6}}}{{\text{C}}^{{\text{12}}}}{{\text{,}}_{\text{6}}}{{\text{C}}^{{\text{13}}}}{{\text{,}}_{\text{6}}}{{\text{C}}^{{\text{14}}}}$ Where the total number of protons is same i.e, ${\text{6}}$ and the total number of neutrons are different

Uranium has got two isotopes
$_{{\text{92}}}{{\text{U}}^{{\text{235}}}}{{\text{,}}_{{\text{92}}}}{{\text{U}}^{{\text{238}}}}$ Where ${\text{92}}$ is the total number of protons and the number of neutrons are different i.e.,${\text{235}}$ and ${\text{238}}$

Hydrogen has three stable isotopes i.e, Protium, Deuterium and Tritium
$_{\text{1}}{{\text{H}}^{\text{1}}}{{\text{,}}_{\text{1}}}{{\text{H}}^{\text{2}}}{{\text{,}}_{\text{1}}}{{\text{H}}^{\text{3}}}$

So, the statement is true.

Additional Information:
Some of the isotopes are called to be radio isotopes if the isotope of an element is radioactive. Each element has at least one radioisotope. Eg: The Cobalt - 60 isotope of Cobalt Is radioactive thus it is considered as radio isotope or radio - cobalt. Many other isotopes of elements are radioisotopes like radio - iodine radio - sodium radio - iron radio - carbon radio - phosphorus Uses of radioisotopes
1. Overactive thyroid glands can be treated using radio - iodine and radio - cobalt is used to treat cancer
2. Radio - phosphorus finds its applications in agriculture inorder to determine the type of phosphate required for the given crop and soil
3. The age of fossils and archaeological specimens can be determined by radio - carbon

Note: Radioisotopes are also used for many diagnostic purposes. Isotopes can also be prepared artificially. In a chemical reaction isotopic labelling can be used to track the passage of an isotope through the reaction.