1. Bohr Rutherford and Lewis Dot Diagrams
Chemistry diagrams
Bohr Rutherford and Lewis Dot Diagrams

2. Recall the Atom
ATOMIC NUMBER: denotes the number of protons and electrons in an atom
ATOMIC MASS: denotes the number of protons plus neutrons in the nucleus of an atom

3. How Do You Find Number of Neutrons
# of Neutrons = ATOMIC MASS – ATOMIC NUMBER
EXAMPLE: How many neutrons are there in a Silicon atom?
SOLUTION: 28 -- 14 =
Atomic Mass
Atomic Number
Number of Neutrons

4. Bohr Rutherford Diagrams
Used to show the atomic structure of an atom, isotope or ion.

5. Bohr Rutherford Diagrams
RULES for drawing Bohr Rutherford diagrams:
Place the number of protons and neutrons in the nucleus of the atom
Place TWO electrons in the first shell. This shell takes a MAX of two electrons.
Place a MAX of eight electrons in all other shells.
OCTET RULE: No shell can have more that EIGHT electrons. If you have extra electrons, add another shell.

6. Practice
Draw a Bohr Rutherford diagram for:
Boron
Fluorine
Argon

7. Lewis dot diagrams
Used to show the number of electrons in the outer shell of an atom

8. Lewis dot diagrams RULES for drawing Lewis Dot Diagrams
Write the chemical symbol for the element.
Determine the number of electrons in the outer shell of that element.
Add electrons starting at the top of the chemical symbol and working CLOCKWISE around the symbol.
You MUST add ONE electron to each side of the symbol BEFORE you start pairing electrons.

9. practice Draw a Lewis Dot Diagram for the following elements: Boron
Fluorine
Argon