1. Ch. 2 Part 1 Chemical Level of Organization

2. Chemistry Review You should already know this! If you don’t, make notes. What are: atoms nucleusprotons neutrons electronsenergy levels atomic number mass numbermolecule compound cationanion ionic bond covalent bondchemical reaction reactants products

3. Atoms Atoms – smallest units of matter Have a nucleus – center – Protons – positive, live in nucleus – Neutrons – neutral, live in nucleus – Electrons – negative, live in energy levels

4. Periodic Table

5. Atomic number – big number on periodic table, tells the number of protons Mass number – small number on periodic table, tells the number of protons + neutrons IN A NEUTRAL ATOM – the number of protons = the number of electrons Practice – Neon, gallium, zirconium, chlorine

6. Compounds vs. Molecules Compound – contains 2 or more different elements – Examples – H 2 O, NaCl, MgCl 2 Molecules – contains 2 or more atoms that share electrons – Examples, H 2 O, O 2

7. Bonding 2 Types – ionic and covalent Ionic bonds – occur between ions, atoms give/take electrons Covalent bonds – occur between atoms, atoms share electrons

8. Ionic Bonds Ions give or take electrons Cations - + ions Anions – ions When put together properly, compound should be neutral Practice: sodium and chlorine – Na is a cation (Na+), chlorine is an anion (Cl-) – NaCl

9. Covalent Bonds Atoms share electrons Must meet the octet rule – each atom must have 8 electrons Use Lewis structures for help We will not worry about bonding angles or shape