2 Making a Bohr ModelBohr Model diagrams are used to represent the electron structures of elementsProtons and neutrons are placed in the middle to represent the nucleusElectrons are placed in the electron shells
3 How to Construct Bohr Model Diagrams Using the example Fluorine, we will work through the steps in creating a Bohr modelRight now, look at your periodic table and find the element Fluorine.Draw in what Fluorine looks like on the Periodic Table in the box on your sheet
4 Steps to Make a Bohr Model Determine the number of subatomic particles found in the elementNumber of electrons is equal to the number of protons in the neutral atom. This value is equal to the atomic numberNumber of neutrons is calculated using the equation Atomic Mass MINUS Atomic Number
5 Steps to Make a Bohr Model Fluorine ExampleNumber of protons = 9Number of electrons = 9Number of neutrons = 19 – 9 = 10
6 Steps to Make a Bohr Model 2. Draw a circle for the nucleus with the correct number of and symbol for both protons and neutrons.Letter symbol for protons: pLetter symbol for neutrons: nFluorine examplep9n10
7 Steps to Make a Bohr Model 3. Draw the correct number of electron shellsFirst ring has a maximum of 2 electronsSecond ring has a maximum of 8 electronsThird ring has a maximum of 8 electrons*Electron shells must be filled to their maximum before another ring is added
8 Steps to Make a Bohr Model FLUORINE EXAMPLEFluorine has 9 electronsThe first electron shell has 2 electrons9 minus 2 = 7The second electron shell will have 7 electrons** The electrons in the outer shell are referred to as valence electrons.
9 Steps to Make a Bohr Model 4. Represent electrons as dots and position electrons in shells.The electron shells are also referred to as electron orbitalsThe electrons will fill the orbit of the lowest energy level first (i.e. first electron shell closest to the nucleus). The first shell can hold a maximum of 2 electrons
10 Steps to Make a Bohr Model An electron shell must be filled with its maximum number of electrons before any additional electron shells can be filledElectrons should be distributed evenly and neatly throughout the shellFLUORINE EXAMPLEIn the Fluorine atom, the first shell contains 2 electrons and the second contains 7 electrons.