1. Pure substance – element and compound
Sodium bicarbonate
NOT solutions (small %compound, large %water)

3. history Dalton – dot Thomson – electron, cathode ray
Rutherford – nucleus, empty space, gold foil
Neutron after (chadwick)
Bohr – quantized energy with light
Quantum model - orbitals

4. atomic structure cobalt – 58 : mass number p + n
Atomic number = protons and electrons in neutral
Weighted average based on the % abundance data of isotopes
Isotopes!

5. Ionic vs. covalent bonding
Ionic: transfer, covalent: share.
Ionic: low and high EN, covalent both high EN
Ionic: crystal lattice, strong bond, covalent: molecule, weaker bond

6. Periodic trends Ionization: increases across, decreases down
Radius: decreases across, increases down
Biggest: N, O P, S? Rb, Sr, S, Cl?
Smallest ionization: N, O, P, S?
Biggest ionization: Rb, Sr, S, Cl?