The Bohr Model of the Atom

1. The Bohr Model of the Atom

2. What do we need to know? • Atoms have 2 main parts • Electron cloud -- contains electrons • Nucleus – central part of the atom, contains protons and neutrons

3. Subatomic particles • Symbols for each subatomic particle • Electrons = e- • Protons = p+ • Neutrons = n0

4. What do you need to know? • Orbitals are found around the nucleus • There are 7 possible orbitals • Orbitals are determined by by looking at what period (row) the element is in • The orbitals hold a specific number of electrons (which is the same as the atomic number)

5. How many electrons per orbital? Period 1 orbital (ring) 1: 2 e- Period 2 orbital (ring) 1: 2 e- orbital (ring) 2: 8 e- Period 3  orbital (ring) 1: 2 e- orbital (ring) 2: 8 e- orbital (ring) 3: 8 e- Period 4 orbital (ring) 1: 2 e- orbital (ring) 2: 8 e- orbital (ring) 3: 18 e- orbital (ring) 4: 8 e-

6. Information to create a Bohr model Atomic # = Protons and Electrons • Element name and symbol: • Magnesium (Mg) • Atomic number: 12 • Atomic mass: 24 • Protons: 12 • Electrons: 12 • Neutrons: (24 - 12) = 12 12 Mg 24.305 Magnesium Atomic Mass

7. Bohr model for Mg Nucleus 12p+ 12n0

8. Bohr model for Al 13p+ 14n0

9. Questions??