1. B1: CLASSIFYING MATTER

2. B1-1: WHAT ARE ELEMENTS?

3. I. BUILDING BLOCKS OF MATTER  Matter is everything that takes up space and has matter.  Matter can be found in:  The food we eat  The water we drink  The air we breathe  Matter may feel different, have different smells, or may appear differently  As a matter of fact, there are over 100 substances in our world!

4. I. BUILDING BLOCKS OF MATTER  Elements  Substances that cannot be broken down into other substances by heat, light, or electricity.  Examples: Iron, Gold, Oxygen  Why are they “Building Blocks”?  Each element is like a letter of the alphabet.  Different combinations make-up different substances found in our world.

5. I. BUILDING BLOCKS OF MATTER GoldAluminum

6. I. BUILDING BLOCKS OF MATTER SulfurOxygen

7. I. BUILDING BLOCKS OF MATTER  Aristotle  Believed matter to made of four basic substances:  Earth, Air, Fire, and Water  He thought that all other substances were made of a combination of the four basics.  Ancient peoples often used elements such as gold, silver, and mercury without realizing they were elements.

8. I. BUILDING BLOCKS OF MATTER  Scientists had been trying to identify all the “building blocks of matter” for hundreds of years.  Scientists often experimented with hundreds of substances as they searched for new elements.  They broke down common substances, such as salt, into their basic parts. (Proof that salt was not an element!)

9. I. BUILDING BLOCKS OF MATTER  With all the work of scientists, you may ask the question, “How do we classify these elements?”  Elements are grouped by their common properties and characteristics.  These groups are:  Metals  Nonmetals

10. I. BUILDING BLOCKS OF MATTER  Metal  Characteristics include:  Shiny  Thermal conduction(heat)  Electricity  Malleability (Change shape)  Example:  Copper  Iron  Gold

11. I. BUILDING BLOCKS OF MATTER  Nonmetal  Not shiny  Heat and electricity to not pass through easily  Malleability limited  Examples:  Oxygen  Carbon  Sulfur

12. II. THE PERIODIC TABLE  Scientists tried to classify and arrange the elements into easy-to-read charts.  In 1869, Dmitri Mendeleev discovered that by arranging elements by the masses, the order came very naturally.  He also arranged the element by their unique properties in rows and columns.  Once he found where each known element should be placed, he left space for elements to be discovered later.

13. II. THE PERIODIC TABLE

14.  Each element on the table has information to distinguish it for every other element.  These parts include:  The Element’s name  The Element’s symbol  The Element’s number

15. II. THE PERIODIC TABLE  Let’s examine the period table on p. B12- B13.  Let’s find:  Hydrogen  Silver  Uranium  Neon  Aluminum  Potassium

16. III. ATOMS  The structure of an Atom:  Atom: The smallest particle of an element that has the properties of the element  Nucleus: The center of an atom, where protons and neutrons are located  Proton: A particle in an atom that has a positive electrical charge (+)  Neutron: A particle in an atom that has no charge  Electron: A particle in an atom that has a negative electrical charge (-)  On the board, copy down the hydrogen atom diagram.

17. III. ATOMS  All atoms of an element have a particular number of protons.  The element’s number in the periodic table depends upon the number of protons found in the nucleus.  Oxygen-Atomic Number 8 = 8 protons  Gold- Atomic Number 79 = 79 protons

18. III. ATOMS  Elements have the same number of electrons as protons.  Elements can have different numbers of neutrons, because they have no charge!!!