Here's a breakdown:
* Protons: Positively charged particles found in the nucleus of an atom.
* Neutrons: Neutrally charged particles found in the nucleus of an atom.
* Electrons: Negatively charged particles that orbit the nucleus.
Example:
* Carbon-12 has 6 protons and 6 neutrons. Its mass number is 12 (6 + 6 = 12).
Key points to remember:
* The mass number is an integer (whole number).
* It is represented by the superscript to the left of the element's symbol (e.g., ¹²C).
* The mass number is not the same as the atomic mass, which is the average mass of an atom of that element, taking into account the different isotopes.
