1. Early History of Atomic Theories
Section 3.1
Early History of Atomic Theories

2. Dalton’s Theory Matter is made up of indestructible atoms.
Law of definite proportions:
Elements combine in a characteristic ratio
Law of multiple proportions:
Some elements have more than one combining capacity
Law of conservation of mass:
Atoms cannot be created nor destroyed

3. Thomson’s theory “The Raisin Bun” model: Gave us electrons
+ and – charges are mixed together
Gave us electrons
Atoms can gain or lose electrons to form ions
Said that the identity of an element was based on its number of electrons

4. Rutherford’s Theory
Atoms have a tiny nucleus which contains positive & neutral charges and makes up the majority of the mass of the atom
Electrons are negative and occupy most of the volume of the atom.
Protons tell us the identity of the element

5. Isotopes
Have the same number of protons and electrons but have different amounts of neutrons.
Radioisotopes – give off radioactivity when they decay

6. Seatwork Pg. 166 #4, 5 Read the Case Study – Pg. 167-168
Summarize the important information