Chapter 5, Problem 3STP

Interpretation Introduction

Interpretation: The statements that characterize the nucleus of every atom need to be identified.

Concept Introduction:

An atom is composed of electrons, protons, and neutrons. Here, protons and neutrons are present in the nucleus of an atom and electrons are present in atomic orbitals around the nucleus.

Answer to Problem 3STP

The correct option is (A).

Explanation of Solution

Reason for correct option:

The three subatomic particles are proton, neutron, and electron. Here, the proton is a positive charge, the electron is negative charge and neutrons have zero charges. In an atom, protons are present in the nucleus of atom. Thus, the nucleus has a positive charge.

Therefore, the statement I is correct.

In an atom, there is no mass of electrons, but protons and neutrons have great mass. Thus, the nucleus has all mass of an atom. Due to its great mass and small size, the nucleus is dense.

Therefore, statement II is correct.

Since both statements I and II are correct, the correct option is (A).

Conclusion

Reason for incorrect options:

The nucleus is composed of protons and neutrons only. Electrons are not present in the nucleus of an atom, but they are present in the atomic orbitals around the nucleus. Thus, statement III is incorrect.

Since the III statement is not correct, options (B), (C), and (D) are incorrect options.