Chapter 4, Problem 3STP

Interpretation Introduction

Interpretation : The true statement about the thallium isotopes is to be identified.

Concept Introduction : Atoms that have various numbers of neutrons and different masses but the same number of protons are called isotopes.

Answer to Problem 3STP

Option (B).

Atoms of both isotopes have 81 protons

Explanation of Solution

Isotopes are atoms of the same element that differs in the number of neutrons but has the same number of protons and electrons.

Due to the different numbers of neutrons, the mass number also changes.

Thallium has two types of isotopes. It contains 81 protons and 81 electrons.

Among the given statement, atoms of both isotopes have 81 protons is the true statement.

Conclusion

Thallium-203 is less than Thallium-205 occurrence in nature.

Thallium-205 has more neutrons than Thallium-203.

The atomic mass of thallium is different.