1. Bohr – Electrons not in nucleus:
Electrons travel in orbitals around the nucleus
Dalton – tiny solid balls
Thompson: atom is like a muffin
Rutherford: electrons move randomly
The History of the Atom
Nagaoka - atom structure-like solar system
Chadwick - discovered neutron

2. Atomic Mass = protons + neutrons
ATOM STRUCTURE
Nucleus
Proton(+)
Neutron: No Charge
Electron(-)
Atomic Number:
# of protons in element
Equal to protons
Not in nucleus
Atomic Mass = protons + neutrons
To find # of Neutrons: Atomic Mass – Atomic #

3. Organized by Increasing atomic # Left to Right
PERIODIC TABLE
Organized by Increasing atomic # Left to Right
Periods: Horizontal = the # of energy levels.
1st Level: 2 electrons(max)
2nd Level: 8 electrons(max)
3rd Level: 18 electrons(max)
7 Periods
Columns: Vertical – Group/Family
Similar Properties
Same # of Valence Electrons
18 Families
Nonmetals – Right (most gas)
Metals – Left (most solid)
Metalloids – on zigzag line
Elements to the left have + ionic charge and elements to the right have - ionic charge
Gain Electrons and have an ionic charge of -
Loose Valence Electrons and have an ionic charge of +

4. C PERIODIC TABLE KEYS AND LEGENDS Element Squares
Background Color: metal, nonmetal, metalloid
Symbol Color: State of Matter 6 C
Carbon 12
Atomic #
Symbol
Element Name
Atomic Mass
Mendeleev – original table – atomic mass

5. ELEMENTS / MOLECULES / COMPOUNDS
Elements – can’t be broken down
Molecule: two or more atoms chemically combined
Compound: two or more molecules chemically combined
Electron Dot Diagram: # of valence electrons only
Covalent Compound: nonmetal +nonmetal
Ionic Compound: metal + nonmetal
Positive Ion
more protons
Negative Ion
More electrons

6. Endothermic: absorbs heat – cooling effect
Types of Reactions
Endothermic: absorbs heat – cooling effect
Exothermic: releases heat – warming effect
Prefixes
Mono – 1
Di – 2
Tri – 3
Quatro – 4
Penta -5
Single Replacement:
Fe + H2O Fe3O4 + H2
Chemical Equation Parts:
Reactant + Reactant Product

7. C Cl Cl + Cl Cl Lewis Structures: Electron Dot Diagram
Element: Valence electrons only
Lewis Structure for Compounds:
Chlorine + Chlorine C Cl Cl + Cl Cl

8. 1. Write element symbols for all elements as
an addition problem.
2. Write each element with enough room to show electron dot structure
3. Show bonding by venn diagram of electrons in bond
4. Draw and build model of compound
5. Show compound in simple written form with bond.
6. Label as covalent or ionic
7. Write formula for compound