2. Who are the following persons and what is their contribution to atomic theory.

J. J. Thompson

John Dalton

Ernest. Rutherford

R. Millikan

Marie Curie

3. The weight percent of oxygen in CaCO3 is __________ %

4. 4.5 mL of a liquid of density 0.934 g/mL would weigh ________ g

5. Write the formula of the following substances and give a short description of the differences in the associated terminology.

a) atomic nitrogen

b) molecular nitrogen

c) a compound of nitrogen

d) elemental nitrogen

e) an isotope of nitrogen

f) the nitride ion

g) the nitrate ion