What Is the Definition of a Proton?

Atoms are all around us and in us. Every atom is made up of electrons spinning around an inner nucleus of protons and neutrons. The number of protons in the nucleus determines the kind of atom it is, whether it's hydrogen, oxygen or some other element.

Size

Protons, like neutrons and electrons, are very tiny things. As small as it is, an atom is over 10,000 times bigger than its protons. The proton weighs in at 1.6 trillion-trillionths of a gram.

Charge

Protons have a positive electric charge. Electrons are negative, and neutrons have no charge. When an atom has the same number of protons and electrons, the charges balance out, and the atom is neutral overall.

Identical

All protons are exactly the same. They all have the same size, mass and electric charge. Likewise, neutrons are all the same, being a little heavier than the proton. Electrons have one-thousandth the weight of the proton, and they, too, are all the same.

Elements

Every element's identity depends on the number of protons. Some elements are unstable, losing protons to radioactive decay. If this happens to an atom, it becomes a different element.

Acids

In acids, hydrogen loses its only electron and becomes a naked proton. This is temporary; the naked proton will take another electron and become a neutral atom again.