1. ATOMIC STRUCTURE Notes are for your personal use. Abbreviate as you see fit.

2. Atomic Structure Atoms are the smallest WHOLE PIECE of matter, or building blocks to make all solids, liquids & gases Atoms can be broken down into 3 types of SUBATOMIC PARTICLES

3. SUBATOMIC 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

4. SUBATOMIC PARTICLES 3. ELECTRONS- negative electrical charge, found moving around the nucleus in the ELECTRON CLOUD

5. Atomic Structure NUCLEUS Electron cloud

6. Atomic Structure 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

7. Atomic Structure ENERGY LEVELS or SHELLS hold different amounts of electrons There are exceptions to the rule, but the basic idea is:

8. Atomic Structure Level 1 holds 0 to 2 electrons Level 2 holds 0 to 8 electrons

9. Atomic Structure Level 3 holds 0 to 8 electrons Level 4 holds 0 to 18 electrons

10. How to find atomic structure Check the PERIODIC TABLE OF ELEMENTS Created by Dimitri Mendeleev in 1869 Page 134-135 in your text

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

12. How to find atomic structure ATOMIC MASS = # of protons PLUS neutrons in the nucleus Neutrons give mass to an atom, making some elements “heavy” or “light”

13. How to find atomic structure Atomic Mass- Atomic Number = # of neutrons Neutrons usually increase as the atomic number increases. This means as atoms hold more protons, they usually hold more neutrons too!

14. How to find atomic structure To find the number of electrons in an atom, check the atomic number. For every positive proton, an atom will have a negative electron

15. The Search for STABILITY Overall neutral charge. PROTONS = ELECTRONS For every positive proton, an atom will have a negative electron

16. The Search for STABILITY Electron Pairs: to be “happy” or for opposite spin pairs Full Energy Levels 2, 8, 18.... Bonding with other atoms to form MOLECULES

17. THE END Stay tuned for other exciting presentations on Physical Science