1. Let’s go WABAC in Time for Your “Do Now” We’ve already talked about how ancient alchemists thought there were five elements. What are they? Hint: Originally there were four, but then a fifth was added. Earth, Air, Water, Fire and Ether or Metal

2. It’s Element-ary An Introduction to Elements

3. Same Idea, Different Definition According to Robert Boyle, an Irish scientist of the 1600’s: An element is a substance that cannot be broken down into two or more simpler substances. Better methods means more elements

4. Testing the Theory Alchemical Element Air Earth Water Fire Ether Broken to Pieces Gases in the air Dirt, Rocks, Clay which can be further broken down Closest  Hydrogen and Oxygen Heat and Light  not elements Doesn’t exist

5. The Periodic Table Over 100 Pieces, and Growing

6. Element Symbols Each element has a unique symbol. The symbol may have either one, two, or three letters. The first letter is always capitalized. The other letters must be lower case.

7. Where Did That Symbol Come From? Sometimes it seems obvious. The symbol is the letter(s) that start the element name. Hydrogen  H Oxygen  O Neon  Ne Silicon 

8. Where, Part II Sometimes it is letters from within the name. Chlorine  Cl Magnesium  Mg Manganese  Mn Zinc  Zn Ununnilium  Uun

9. Where, Part III Sometimes the symbol is based on a historical name for that element. Gold  aurum  Au Lead  plumbum  Pb Sodium  natrium  Na Iron  ferrum  Fe

10. Is It an Element? Start with your substance. Is it made of more than one chemical? YES It is a mixture, not an element. NO It is all one chemical. Does the chemical formula have more than one type of chemical symbol? YES It is a compound, not an element NO It is an element

11. Three Kinds of Elements A sample –Example: 24k gold is elemental gold A molecule –Example: O 2 is elemental oxygen An atom –Example: Ne is elemental neon

12. The “Not Elements” A compound is a formula that has more than one element symbol. –Examples: CO 2 and H 2 O –May be molecules or samples A mixture is a sample that is made up of molecules with different formulas. –Examples: Air, Ocean Water, Kool-Aid

13. Homework Read: Chapter 3 Sections 3 and 4