Question 47

Electrons are equal in number to protons in a neutral atom.

In an atom with no net charge, the number of electrons is equal to the number of protons. This balance ensures that the positive and negative charges cancel each other out, resulting in a neutral charge.

A) number of protons

This option is correct because, in a neutral atom, the total positive charge from protons is balanced by the total negative charge from electrons. Therefore, the number of protons must equal the number of electrons, maintaining the atom's overall neutrality.

B) number of neutrons

This option is incorrect. The number of neutrons does not affect the charge of the atom, as neutrons are neutral particles. While neutrons contribute to the mass of the atom, they do not influence the charge balance between protons and electrons.

C) sum of the numbers of neutrons and protons

This option is incorrect as well. The sum of neutrons and protons gives the atomic mass but does not relate to the charge of the atom. The charge balance specifically involves only electrons and protons, not neutrons.

D) number of neutrons divided by the number of protons

This option is also incorrect. The ratio of neutrons to protons does not determine the charge of an atom. Instead, it is the equality of the number of electrons and protons that maintains a neutral charge.

Conclusion

The correct answer is A, as it accurately reflects the fundamental principle that in a neutral atom, the number of electrons equals the number of protons. All other options fail to address the charge balance directly and either misinterpret or overlook the role of neutrons in this context.