1. The Bohr Model of the Atom DO NOT WRITE ON THESE NOTES COPY THESE NOTES IN CORNELL STYLE IN YOURBINDER.

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- (found in the electron cloud) – Protons = p+ (found in the nucleus) – Neutrons = n 0 (found in the nucleus)

4. What do you need to know? Orbitals are found around the nucleus – There are 7 possible orbitals – Orbitals are determined 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) Period 1 Period 2 Period 3 Period 4 Period 5 Period 6 Period 7

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 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 # = Protons and Electrons Atomic Mass Atomic Mass – Atomic # = Neutrons

7. Bohr model for Mg 12p + 12n 0 Nucleus Orbital 1 can only hold a maximum of 2 electrons Orbital 2 can only hold a maximum of 8 electrons Orbital 3 can only hold a maximum of 8 electrons, but you only use the # of electrons you need. Electrons are represented by the dots. Magnesium will have 3 orbitals because it is in period #3 When you add all the dots (electrons) you should get 12.

8. Bohr model for Al Aluminum is in period #3 and has 13 electrons. 13p + 14n 0

9. Your Assignment! This goes on a separate piece of paper! Create the Bohr model for elements 1-20 on the periodic table. (Hydrogen (H) – Calcium (Ca)) For each element provide the: – Write the element name: __________________ – Protons= ____ – Electrons= ____ – Neutrons= ____ – Period = _____ = Orbitals= _____ – Bohr Model: