An atom is the smallest particle of an element that can take part in a chemical reaction.
The atoms of an element such as bismuth are made up of subatomic particles protons, neutrons, and electrons.
Protons are the positively charged particles found in the nucleus of an atom together with the neutrons while electrons are the negatively charged particles surrounding the nucleus in energy levels of an atom.
The number of electrons and protons in a neutral atom is equal. Therefore, all neutral atoms of an element such as bismuth have an equal number of protons and electrons.
