Atom Notes

The 3 particles found in an atom are the proton, electron, and neutron.

Protons have a positive charge and are found inside the nucleus.

Electrons have a negative charge and are found outside the nucleus.

Neutrons have no (zero) charge and are found inside the nucleus.

The atomic mass is made up of the mass of both the proton and neutron.

All the mass of an atom is found in the nucleus.

The nucleus contains protons and neutrons.

Electrons are found in the outer cloud called the electron cloud.

Remember APE:

Atomic number = # of Protons = # of Electrons

Remember MAN:

Atomic Mass – Atomic number = Number of Neutrons

Energy Levels

The first energy level can only hold 2 electrons.

The second energy level can only hold 8 electrons.

The third energy level can only hold 8 electrons.

Valence electrons are the electrons found in the outside energy level of the atom.