Bohr Models

Making a Bohr Model Bohr Model diagrams are used to represent the electron structures of elements Protons and neutrons are placed in the middle to represent the nucleus Electrons are placed in the electron shells

How to Construct Bohr Model Diagrams Using the example Fluorine, we will work through the steps in creating a Bohr model Right 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

Steps to Make a Bohr Model Determine the number of subatomic particles found in the element Number of electrons is equal to the number of protons in the neutral atom. This value is equal to the atomic number Number of neutrons is calculated using the equation Atomic Mass MINUS Atomic Number

Steps to Make a Bohr Model Fluorine Example Number of protons = 9 Number of electrons = 9 Number of neutrons = 19 – 9 = 10

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: p Letter symbol for neutrons: n Fluorine example p9 n10

Steps to Make a Bohr Model 3. Draw the correct number of electron shells First ring has a maximum of 2 electrons Second ring has a maximum of 8 electrons Third ring has a maximum of 8 electrons *Electron shells must be filled to their maximum before another ring is added

Steps to Make a Bohr Model FLUORINE EXAMPLE Fluorine has 9 electrons The first electron shell has 2 electrons 9 minus 2 = 7 The second electron shell will have 7 electrons ** The electrons in the outer shell are referred to as valence electrons.

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 orbitals The 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

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 filled Electrons should be distributed evenly and neatly throughout the shell FLUORINE EXAMPLE In the Fluorine atom, the first shell contains 2 electrons and the second contains 7 electrons.

Bohr Model Example