1. CHEMISTRY!!! Yeah baby!

2. Structure of the Atom  Nucleus: The center of an atom. Holds the protons and neutrons.

3. Structure of the Atom: Protons: Positive charge, atomic number  Neutrons: no charge  Both found in the Nucleus!

4. Structure of the Atom  Electrons: Negative charge, orbit the nucleus

5. Structure of the Atom  Atoms on the periodic table have 2 numbers

6. Structure of the Atom  Atomic mass: mass of both the neutrons and protons.  Protons = 1  Neutrons = 1

7. Structure of the Atom  Atomic number: Number of protons  Protons tell you what atom it is!

9. Structure of the Atom  Isotopes: When the number of neutrons differ, changing the atomic mass, BUT atomic number stays the same!

10. Structure of the Atom  Carbon

11. Electron shell  Shells:  1 st shell = 2 electrons  2 nd shell = 8 electrons

12. Electron shell  Complete Shell: no empty sites, full electron count in shell.

13. Element vs. Compound  Element: same kind of atom  Compound: made up of mixed elements

14. Chemical Bonding  There are three types of major bonds:  Ionic  Covalent  Hydrogen

15. Chemical Bonding  The bonds are determined by differences in electronegativity (power of an atom to attract electrons).

16. Chemical Bonding  Ionic: Atom Gives (takes) an electron from another atom and then becomes shell complete.

17. Chemical Bonding  Ionic: One becomes positively charged and one becomes negatively charged.  (Electroneg is ≥ 1.7)

18.  Na  Cl  Na-Cl

19. Chemical Bonding  Covalent: 2 atoms share an electron to become shell complete. It is a stronger bond then Ionic.  (Electroneg is ≤ 1.6)

20.  H =  O =  H-O-H

21. Chemical Bonding  Hydrogen Bond: Bond formed when hydrogen is in covalent bond with another element, because of unequal sharing of electrons.

22. Chemical Bonding  Hydrogen Bond: Atoms become polar with Hydrogen side having a slight positive side. Allowing a weak bond with negative ion.

23. Practice:  Worksheet.

24. Some Atoms are Sociable, Others Aren’t Atoms “want” (are most stable) to have a filled outer electron shell. Atoms without a filled outer shell will share electrons with other atoms to accomplish this “goal.” Filling outer electron shells controls which atom will pair with which others and in what combinations.

25. Filling Electron Shells An important rule: the innermost shell holds two electrons; subsequent shells hold 8 electrons.

26. Pairing for the Greater Good When atoms come together by sharing electrons the bond is a covalent bond. H2H2 A molecule is formed when two or more atoms are bound together covalently.