Which statement best explains why the overall charge on an atom is zero?

a. The positive charge of the neutrons in the nucleus equals the negative charge in the electron cloud.

b. The positive charge of the protons in the nucleus equals the negative charge in the electron cloud.

c. The negative charge of the neutrons in the nucleus equals the positive charge in the electron cloud.

d. The negative charge of the protons in the nucleus equals the positive charge in the electron cloud.

b. The positive charge of the protons in the nucleus equals the negative charge in the electron cloud.

Explanation:

The electron is subatomic particle that revolve around outside the nucleus and has negligible mass. It has a negative charge.

Symbol = e⁻

Mass = 9.10938356*10⁻³¹ Kg

It was discovered by j. j. Thomson in 1897 during the study of cathode ray properties.

While neutron and proton are present inside the nucleus. Proton has positive charge while neutron is electrically neutral. Proton is discovered by Rutherford while neutron is discovered by James Chadwick in 1932.

Symbol of proton = P⁺

Symbol of neutron = n⁰

Mass of proton=1.672623*10⁻²⁷ Kg

Mass of neutron=1.674929*10⁻²⁷ Kg

An atom consist of electron, protons and neutrons. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.

All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. In other words we can say that negative and positive charges are equal in magnitude and cancel the each other. For example if neutral atom has 6 protons than it must have 6 electrons and overall charge on atom is zero and it is said to be neutral. The sum of neutrons and protons is the mass number of an atom while the number of protons are number of electrons is the atomic number of an atom.

For example

The carbon have six protons and six neutrons so its atomic mass is 12 amu and atomic number is six.