Question

Which of the following are characteristics of isotopes of an element?
(i) Isotopes of an element have the same atomic masses.
(ii) Isotopes of an element have the same atomic number.
(iii) Isotopes of an element show the same physical properties.
(iv) Isotopes of an element show the same chemical properties.

• A. (i),(iii) and (iv)
• B. (ii) ,(iii) and (iv)
• C. (ii) and (iii)
• D. (ii) and (iv)

Answer 1

The correct option is D

(ii) and (iv)

Explanation:

Isotopes:

• Isotopes of an element have same the atomic number but different mass numbers or atomic masses.
• Now, the atomic number of an element = number of protons = number of electrons
• Therefore, the electronic configuration is the same for isotopes and as the chemical properties depend upon the electronic configuration, so the chemical properties are the same for the isotopes.

Example: Chlorine has two isotopes which are shown below:

${}_{17}{}^{35}\mathrm{Cl}\mathrm{and}{}_{17}{}^{37}\mathrm{Cl}$

• Hence, the statements (ii) and (iv) are correct.

Therefore, option (D) is correct.