Summary Chemistry first semester review

2.1 - Dalton’s Atomic Theory
1. Law of Conservation of Mass
2. Law of definitive proportions
a. All samples of a pure compound will have the same amount of each element by
weight
b. Will always be 6 Cs and 6 Hs in C6H6, if u change the number its not the same
compound
3. Law of Multiple proportions
a. The same two elements, if they form different compounds, the relationship
between the numbers of each will be in simple whole number ratios
b. The ratio of Hydrogens to each other is a whole number ratio in H2O - 2 to 1
2.2 - Evolution of Atomic Theory
● Dalton gave us the theory of the atom, now we’re looking at experiments that led to the
subatomic particle discovery
● JJ Thompson
○ Determined that there were negatively charged atoms in the nucleus
■ Called them electrons
● Milikan
○ Charged oil drops and watched the rate at which they fell toward the other
negatively charged plate
○ Discovered the charge and mass of electrons
● Rutherford
○ Protons + nucleus
● Chadwick
○ Neutrons
● Pierre or smth
○ Isotopes
2.3 - Atomic Mass
2.4 -
● Molecular Formula
○ C6H6
● Empirical Formula
○ CH
● Cation
○ Positively charged ions
● Anion
○ Negatively charged ions
● Ions make ionic compound, atoms make covalent compounds
● Isomers
○ Have the same molecular formula but different structural formula