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Warm Up. What did Neils Bohr discover about atoms? Why was this discovery so important?. Atomic Notation. Sometimes, elements are represented in atomic notation. This is usually true when they are not seen on the periodic table The top number is the Mass number and the
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Warm Up • What did Neils Bohr discover about atoms? • Why was this discovery so important?
Atomic Notation • Sometimes, elements are represented in atomic notation. • This is usually true when they are not seen on the periodic table • The top number is the Mass number and the Bottom number is the Atomic number. YOU CAN TELL THE DIFFERENCE BECAUSE THERE IS NO BOX AROUND THE ELEMENT SYMBOL
Practice What is the atomic #? What is the atomic mass?
Drawing Bohr-Rutherford Diagrams • Electrons are found in atoms in ENERGY LEVELS • Each ring is called a SHELL • The outermost electrons are called VALENCE electrons • In the periodic table, elements can be found arranged by its number of valence electrons
Shells The first shell can only hold 2 electrons. The second, third, and fourth shells can hold 8 electrons. Fill in the electrons starting at the center and working your way out.
Watch a demonstration… http://youtu.be/sKAzHE7A7rQ As you watch the second demonstration, draw along with the presenter. You will be drawing a diagram for phosphorous. http://youtu.be/M4dfgCfLNE8
Get a blank sheet of paper • Your assignment is to draw Bohr Rutherford diagrams for the first 20 elements of the periodic table. • If you do not finish, they are due for homework on Monday! • There is a Periodic table on the back inside cover of your book and one in your agenda.