Chapter 6, Problem 19STP

Interpretation Introduction

Interpretation: Whether the first statement and second statement are correct or not needs to be explained. Whether the second statement is the correct explanation for the first statement needs to be explained.

Concept introduction: Proton has a positive electric charge and has a mass of $\text{1}{\text{.67×10}}^{\text{-27}}\text{kg}$ . Neutrons do not have an electric charge and have a mass of $\text{1}{\text{.67×10}}^{\text{-27}}\text{kg}$ . The mass of both proton and neutron are same.

Answer to Problem 19STP

Both the first and second statements are true and the second statement is the correct explanation of the first statement.

Explanation of Solution

The first statement states that the symbol for an alpha particle is $\text{H}\text{e}$ . In the molecule $\text{H}\text{e}$ the atomic number is 2, and atomic mass is 4. Hence, the statement is true as an alpha particle has two neutrons and two protons.

The second statement states that protons and neutrons have about the same mass. The mass of a proton is $\text{1}{\text{.67×10}}^{\text{-27}}\text{kg}$ and the mass of a neutron is $\text{1}{\text{.67×10}}^{\text{-27}}\text{kg}$ . From this, one can conclude that both the proton and neutron have the same mass. Hence, this statement is correct explanation for the first statement.

Conclusion

Since the mass no of both proton and neutron is same, it can be concluded that both the first and second statements are true and the second statement is the correct explanation of the first statement.