Question

Isotopes are?

• A. Atoms of an element with similar chemical properties but different atomic masses.
• B. Atoms of different elements with similar chemical properties but different atomic masses.
• C. Atoms of an element with different chemical properties but the same atomic masses.
• D. Atoms of different elements with different chemical properties but same atomic masses.

Answer 1

The correct option is A

Atoms of an element with similar chemical properties but different atomic masses.

Explanation for the correct option:

Option(A):

• Isotopes of an element possess a similar number of protons and hence the same number of electrons and since the electrons are responsible for chemical properties, isotopes of an element, show similar chemical properties.
• The difference in the atomic number of the Isotopes arises due to the difference in the 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(B):

• Isotopes which has the same chemical properties and different atomic mass belongs to the same single element.
• Hence, the Option does not correspond to the correct concept.

Option(C):

• Isotopes are defined as the atoms of an element with similar chemical properties but different atomic masses.
• Hence, the given Option does not represent the correct answer.

Option(D):

• Atoms of different elements with different chemical properties but same atomic masses do not represent the term called, isotopes.
• Thus, the given option does not coincide with the correct concept.

Hence, Isotopes are atoms of an element with similar chemical properties but different atomic masses.