Atomic Models Bohr Model Cloud Model Bohr Model Electrons orbit the nucleus in definite orbits. The orbits can hold only a specific number of electrons. Once a level is full, the electrons start filling the next level. Electron Level Limits: 1st Level = 2 electrons 2nd Level = 8 electrons 3rd Level = 8 electrons Hydrogen: + - Helium: Lithium: Beryllium Cloud Model: The electrons are in an area around the nucleus called an electron cloud. There are enough electrons to make the atom’s charge neutral Hydrogen: 1P 0N 1E Helium: 2P 2N 2E Lithium 3P 3N 3E Assignment: Draw a Bohr Model and a Cloud Model for the first 18 Atoms on the Periodic Chart. Include the Atomic Number and Mass. You may write rather than draw the number of protons and neutrons there are in the nucleus, but draw all electrons for the bohr model.