1.2 Atomic Structure

Elements are arranged in order of atomic number in the periodic table.

The atomic number (proton number) is equal to the number of protons in the nucleus of the atom.

The nucleus is made of protons and neutrons this combined equal the mass number.

Electron - negative (-1) charge, orbits the nucleus in shells, little mass

Proton - positive (1) charge.

Neutron - no charge (0).