1. Chemistry Notes Part 1

2. Elements
Something that can not be broken down into a simpler form and maintain characteristic properties
Made up of only ONE type of atom

3. Dimitri Mendeleev Russian Scientist
Invented the periodic table of elements
Only 50 known elements
1860s
Predicted new elements
Dimitri Mendeleev

4. Now: 118 known elements #1-92 occur naturally
Only 88 are naturally found on earth

5. Matter “Stuff” or “LEGOS®” of the universe Solid Liquid Gas Plasma
BEC (Bose-Einstein Condensate)

6. Atom Sub atomic particles
Basic unit of an element
Parts of an atom
Electrons: (-)
Orbits nucleus
Protons: (+)
In nucleus
Neutrons: (none)
Atom Sub atomic particles

7. Molecule
≥ 2 atoms bonded together
Ex: H2O
Ex: O2
Ex: CO2

8. Element (Atomic) Number Electron number of an atom Atomic Mass
Atomic # = # of Protons
Typically # of electrons = # of protons
Mass of protons and neutrons

9. Neutron # Atomic mass minus atomic number= # of neutrons
EX: O (Oxygen)
Protons (+) = 8
Electrons (-) = 8
Neutrons (0) = 8 (16-8)=8
Atomic #
Symbol
Name
Atomic Mass

10. Rows Columns Periods Groups of Families
How many electron orbitals (shells) an atom has
Groups of Families
Have similar characteristics and properties
Same # of valence electrons

11. Valence Electrons Outer electrons of an atom
Important for + are responsible for chemical reactions