Proton

Definition

A proton is a subatomic particle found in the nucleus of an atom, carrying a positive electric charge. It plays a crucial role in defining the identity and properties of an element.

5 Must Know Facts For Your Next Test

1. Protons determine the atomic number of an element, which defines the element itself.
2. The number of protons in an atom's nucleus is equal to the number of electrons orbiting the nucleus in a neutral atom.
3. Protons have a relative mass of approximately 1 atomic mass unit (amu), similar to neutrons but much larger than electrons.
4. The strong nuclear force holds protons together within the nucleus despite their positive charges repelling each other.
5. Changes in the number of protons result in the formation of different elements, not isotopes.

Review Questions

• What role do protons play in determining an element's identity?
• How does the number of protons relate to the atomic number?
• Why don't protons repel each other out of the nucleus?

Related terms

Neutron: A subatomic particle found in the nucleus with no electric charge and a mass similar to that of a proton.

Electron: A subatomic particle with a negative charge that orbits the nucleus and has negligible mass compared to protons and neutrons.

AtomicNumber: The number of protons in an atom's nucleus, which uniquely identifies an element.