1. Periodic Table

2. History
Dmitri Mendeleev (1869) arranged the known elements based on atomic mass
Elements with similar properties occurred in regular intervals (periodic)

3. Henry Mosely 1914- rearranged the table based on atomic number once protons were discovered

5. Atomic number- number of protons in one atom of the element
Chemical symbol- Sometimes one letter, sometimes two letters, first letter is always capitalized
Atomic mass- average mass for all naturally occurring isotopes; this is not the same as mass number

6. Element arrangement

7. Metals left of the zigzag few electrons in outer energy level
most are solid at room temperature
shiny, good conductors, ductile (can be made into a wire), malleable

8. Nonmetals right of the zigzag (except hydrogen)
have almost complete or complete outer level of electrons
many are gasses at room temperature
dull, poor conductors, not ductile, not malleable

9. Metalloids
border the zigzag line
half complete set of electrons in outer level
semiconductors
share properties with metals and nonmetals

10. A period is a row (left to right) Seven of them
Periods
A period is a row (left to right)
Seven of them
properties like conductivity and reactivity change across the period
Densest elements are in the middle

11. Groups Groups are columns (top to bottom) 18 groups Also called family
Elements in the same group have similar physical and chemical properties
Same number of valence electrons (electrons in the outermost shell)

12. Valence electrons allow chemical bonding
Group 1 has 1 valence electron
Group 18 has a full set of valence electrons
Group 1 is very reactive, while group 18 does not react with other elements

13. Group 2 = alkaline-earth metals Groups 3-12 = transition metals
Main Names
Group 1 = alkali metals
Group 2 = alkaline-earth metals
Groups 3-12 = transition metals
Groups = named for top element in that group (ex: carbon group)
Group 17 = halogens
Group 18 = noble gases

15. Exothermic reactions- energy is released
Chemical Reactions
Exothermic reactions- energy is released
Product can give off light and/or heat
Endothermic reactions- energy is absorbed
Energy is in the reactants

16. During chemical reactions bonds between atoms break
During chemical reactions bonds between atoms break. Then, the atoms rearrange to make new substances.
The new substance has different physical and chemical properties that the original.
Examples: precipitate forms, odor change, gas produced, etc.

17. Ways to speed up a reaction
Increasing concentration
Increasing surface area (crushing/grinding)
Increase temperature
Adding a catalyst

19. Chemical formulas Symbols and numbers that represent substances
Examples:
Water = H2O
Salt = NaCl
Glucose = C6H12O6
Baking Soda = NaHCO3

20. Chemical Equations

21. RAP
Reactants  Product

22. Subscript Coefficient
The law of conservation of mass means the same number of atoms must be on both side of the equation.
Coefficient
Subscript

23. Video Help Beginning help: https://www.youtube.com/watch?v=yA3TZJ2em6g
More examples: