1. The Atom
Ch 3.1

2. Foundations of Atomic Theory
Law of Conservation of Mass
Mass cannot be created or destroyed
Law of Definite Proportions
Chemical compound always has the same proportions of elements no matter the size
Law of Multiple Proportions
When elements combine, they do so in the ratio of small whole numbers. The mass of one element combines with a fixed mass of another element 

3. Dalton’s Atomic Theory
1. Matter is composed of atoms
2. Atoms of a given element are identical in mass, size, and properties
3. Atoms cannot be created or destroyed
4. Atoms of different elements combine in simple whole number ratios to form compounds
5. In chemical reactions atoms combine, separate or rearange

4. Modern Atomic Theory 1. All matter is composed of atoms
2. Atoms of any one element differ in properties from another element

5. The Structure of an Atom
Ch 3.2

6. Subatomic Particles Electron- Proton- Neutron-
negatively charged, surround the nucleus
Proton-
Positively charged, in nucleus
Neutron-
Neutrally charged, in nucleus

7. Thompson Used cathode rays to discover electrons
Found electrons to be negatively charged particles
Plum Pudding Model
Negative and positive charges spread evenly

8. Rutherford
Used alpha particles to discover the nucleus

9. Composition of Atomic Nucleus
Protons
Neutrons
Positive Charge
Equal in magnitude to the negative chare of an electron(same # of protons and electrons)
Determine atoms identity
Neutral Charge

10. Nuclear Forces Hold nuclear particles together Proton- Proton force
Neutron-Neutron Force
Proton-Neutron Force

11. Counting Atoms
Ch 3.3

12. Atomic Number The number of protons of each atom in the element Z
In order on periodic table

13. Isotopes
Atoms of the same element with different number of neutrons(different mass)

14. Mass Number
Total number of protons and neutrons

15. Designating Isotopes Hyphen Notation Nuclear Symbol
Mass written with a hyphen after the element name
Hydrogen-3
1 Proton
1 Electron
2 Neutrons
Element mass and atomic # written with the elements symbol
Neutrons= Mass-atomic

16. Practice

17. Relative Atomic Masses
Carbon-12 atom
Standard to compare units of atomic mass
Atomic Mass Unit
1amu = 1/12 mass of Carbon-12
Ex:Oxygen-16
Mass 16/12 of Carbon-12
16 amu

18. Average Atomic Mass
Weighted average of atomic masses of naturally occurring isotopes of an element
Calculating AAM
1.Multiply atomic mass of each isotope by relative abundance
2. Add the results

19. Relating Mass to Numbers of Atoms
Mole
Avogadro's Number
Number of particles in a mole
6.022 x 1023
SI unit for amount of substance
Amount of a substance that contains as many particles as are atoms in 12g of carbon-12

20. Relating Mass to Numbers of Atoms
Molar Mass
Gram/Mole Conversion
Mass of 1mole of a pure substance
g/mol

21. Practice

22. Practice

23. Conversions with Avogadro's Number
Avogadro's Number can be used to find
The number of atoms in an element
The amount of an element in moles

24. Practice

25. Practice