Ionic Compounds

Notes for Page 49.
We followed the following PowerPoints during class:
1) Intro to Ionic Compounds
2) Properties of Ionic Compounds

We used this note sheet.

Scientific Notation

Notes for page 35.

Scientists work with very large and very small numbers. writing these nubmers over and over gets repetitive, boring and time consuming. Therefore, scientists developed amn easier way to write these numbers.

Scientific notation is based on multples of ten.
- positive exponents are multpilying by ten
   * the number gets larger
   * The deciman moves to the right
- negative exponents are dividing by ten
  * the number gets smaller
  * The decimal moves to the left

Integrating Significant Figures
- the decimal point always goes behind the first non-zero
- only include the significant figures when converting to scientific notation
- once in scientific notation, only the numbers are significant (NOT the "x 10")

Lewis Dot Structures

Notes for page 37.

Bohr Diagrams show ALL electrons.

Lewis Dot Structures show only the electrons in the last orbital of the Bohr Diagram.
These electrons are called Valence Electrons.

Valence Electrons

• Electrons in the outermost orbital of an atom
• The reactive electrons
• Determine an element's physical and chemical properties
• Found by looking at Group # on the PT (excluding Transition Metals)

Lewis Dot Structures are used to

• Show # of valence electrons
• Show bonding between atoms

How to draw a Lewis Dot Structure:
1) Find the element on the PT
2) Write down the element's symbol
3) Find the element's Group #
4) Draw Valence Electrons around the symbol (starting at the top, moving clockwise, one at a time until all sides are filled, then pair)
How Group # corresponds to Valence Electron #