Question

Isotopes of an element have?

• A. The same physical properties
• B. Different chemical properties
• C. Different numbers of neutrons
• D. Different atomic numbers.

Answer 1

The correct option is C

Different numbers of neutrons

Explanation for the Correct Option:

Option(C):Different numbers of neutrons

• Isotope is defined as a substance that has the same atomic but different mass number.
• Isotopes of an element possess a similar number of protons and hence the same number of electrons but a different number of neutrons which can be calculated by calculating the difference between the atomic number mass and atomic number.
• Example: For Hydrogen, there are three types of isotopes, which are Protium, $\left({}_1{}^1\mathrm{H}\right)$ Deuterium$\left({}_1{}^2\mathrm{H}\right)$, and Tritium $\left({}_1{}^3\mathrm{H}\right)$which have the same atomic number and chemical properties but different atomic masses.
• Here, we can say that the isotopes of hydrogen have different atomic masses due to varying numbers of neutrons, i.e for Protium, the number of neutrons is one, and for Deuterium, the number of neutrons is two and in Tritium, the number of neutrons is 3.

Explanation for the incorrect Option:

Option(A): The same physical properties

• The physical properties of isotopes including mass, melting or boiling point, density, and freezing point, are all different.
• Hence, the given Option is an incorrect one

Option(B):Different chemical properties

• When it comes to the chemical properties of isotopes of a given element, they are almost equal or the same due to a similar atomic number or the same number of electrons which represents the chemical properties of any substance.
• Thus the given Option doesn't represent the correct concept.

Option(D):Different atomic numbers

• Since isotopes have the same number of electrons or protons, hence they have the same atomic number but have different mass numbers.
• Hence, the given Option does not coincide with the correct concept.

Hence, Isotopes of an element have different numbers of neutrons.