Atoms

Protons and neutrons are found in the nucleus and are roughly the same size as each other

The number of protons for any given element and is equal to the number of electrons. This is called the atomic number.

  • the atomic number is uniquely characteristic of any given element, and there are no gaps in the list of atomic numbers.

Neutrons carry no charge and play no role in chemical reactions

The protons, neutrons and electrons in any given element are identical to those in every other element.

  • that is, a gold proton is the same as an iron proton. The only thing that makes a gold atom gold and an iron atom iron is the number of protons and electrons it has

In chemical reactions, only electrons are detached or exchanged

  • that’s the difference between chemical reactions and nuclear reactions. Nuclear reactions involve breaking the forces of attraction within a nucleus

Electrons have a negligible mass, so the total mass of an atom (its mass number) is equal to the combined number of protons and neutrons

  • the atomic mass is usually more than double the atomic number, since usually an element has more neutrons than protons in a nucleus.
    • ex. The atomic number of fluorine is 9 and it’s mass number is 19, allowing us to deduce that it has 9 protons and 10 neutrons

Children
  1. Isotopes