2. Atomic Structure Nucleus Outer electron shell Inner electron shell Proton Neutron

3. Sub Atomic Particles 1. PROTONS- positive electrical charge, found in the NUCLEUS, or center of an atom. 2. NEUTRONS- neutral (no electrical charge), also found in the NUCLEUS. 3. ELECTRONS- negative electrical charge, found moving around the nucleus in the ELECTRON CLOUD

4. Friendly electrons Electrons like to travel in pairs, when they can find another electron to travel with. Different layers within the electron cloud are called ENERGY LEVELS or SHELLS

5. Friendly electrons Electrons like to travel in pairs, when they can find another electron to travel with. Different layers within the electron cloud are called ENERGY LEVELS or SHELLS

6. Atomic Number? How many bonds will this form? How many Protons?

7. Electron shells The first shell can hold 2 electrons. The second shell can hold 8 electrons. The third shell also holds 8 electrons.

8. Electrons exist in shells around the nucleus. H 1 p + (1 e - ) He 2 p + (2 e - ) Li 3 p + (3 e - ) C 6 p + (6 e - ) N 7 p+ (7 e - ) O 8 p + (8 e - )

9. How to find atomic structure ATOMIC NUMBER = protons in the nucleus Each different atomic number is a new ELEMENT, or pure substance that cannot be broken down

10. How to find atomic structure ATOMIC MASS = protons PLUS neutrons in the nucleus Atomic Mass- Atomic Number = neutrons

11. Periodic Table Alkali Metals Halogens Noble Gases

12. Information in the Table Ag 107.87 Silver 47 Atomic number Name of the element Elemental Symbol Atomic mass (weight)

13. 109 elements are currently known: (Don’t need to know this!) –87 are metals –26 are radioactive –16 are man made (all radioactive) –11 occur as gases – 2 occur as liquids

14. Navigating the Periodic Table The rows are the “periods” –Each period starts a new shell of electrons –The periods are numbered starting with 1 at the top The columns are the “groups” –Each group has similar chemical properties –The groups are numbered starting with 1 at the left –Elements with similar properties have the same number of electrons in the outermost shell

15. Chemical Families –Group 1 are called alkali metals because the react with water to from an alkaline solution, very soft metals. –Group 7 are the halogens These need only one electron to fill their outer shell They are very reactive.( disinfectants, bleach, headlights) –Group 0 are the noble gases as they have completely filled outer shells They are almost non reactive.