Elements are made of protons, neutrons, and electrons as you may know.
Protons have a positive charge and are found in the nucleus. The atomic number tells how many protons and the number of protons determins the element.
Neutrons have no charge and are also found in the nucleus.
Protons and neutrons together equals the mass of an atom and can have different number of neutrons in the same atom.
Electrons have a negative charge and are the same number as protons for a neutral atom.
The thing I found most interesting in this chapter.... Isotopes. They have different number of neutrons in the same element.
Ions are chared atoms that gain or loose electrons.
