1. The Periodic Table of the Elements

2. Elements: pure substances made of only 1 kind of atom Period: row of elements across table every element in period has same number of shells/orbits Group/Family: column of elements down table every element in same column has same # of valence electrons (e - on outer shell) HowStuffWorks Videos "100 Greatest Discoveries: The Periodic Table“ HowStuffWorks Videos "100 Greatest Discoveries: The Periodic Table“

3. Important Groups Group 1 – Alkali Metals: soft and highly reactive Group 2 – Alkaline Earth Metals: light and reactive Group 17 – Halogens: usually gases, very reactive Group 18 – Noble Gases very stable, do not react

4. HowStuffWorks Videos "100 Greatest Discoveries: Atomic Weight“ HowStuffWorks Videos "100 Greatest Discoveries: Atomic Weight“ Periodic Table: Ferocious Elements - Resources - TES Connect Periodic Table: Ferocious Elements - Resources - TES Connect The Periodic Table

5. Atomic Structure all things are made of matter all matter made of tiny particles called atoms atoms made of 3 kinds of subatomic particles:

6. 1. Protons (p + ) positively charged in nucleus do not move is the atomic number 2. Neutrons (n 0 ) neutral charge in nucleus do not move p + + n 0 = atomic mass

7. 3. Electrons (e - ) negative in orbits around nucleus can be lost, gained, or shared with other atoms