Presentation on theme: "Steps of Scientific Method Experimental variables ? What does experiment do? Scientific Theory vs. Law?"— Presentation transcript:
Steps of Scientific Method Experimental variables ? What does experiment do? Scientific Theory vs. Law?
Chpt 2 - Atoms, Molecules and Ions Atomic Theory - Greeks and Dalton Advances in theory (Sci Method works) –Thomson –Millikan –Rutherford –Chadwick Molecules and Ions Periodic Table - design, group names
J J Thomson Postulated the existence of electrons using cathode-ray tubes. Determined the charge-to-mass ratio of an electron.
Cathode Ray with Field
R. S. Millikan Performed experiments involving charged oil drops. Determined the magnitude of the charge on a single electron. Calculated the mass of the electron.
E. Rutherford Atom has a dense center of positive charge called the nucleus. Electrons travel around the nucleus at a relatively large distance.
Atomic / Nucleus Size
Chadwick Novel experiment to discover missing mass in the atom (nucleus) Why difficult to observe?
Periodic Table Who ? How is it organized? Know the group and series names, metals, nonmetals, metalloids, solids, liquids, gases
Chpt 2 - Nomenclature Names Chemical formulas Binary and Polyatomic Ionic per -ate, -ate, -ite, hypo -ite Roman numerals ( ) if necessary in the formula Molecules (prefixes) Acids –Without oxygen –With oxygen
Nomenclature Metal 1st -> ionic compound –Binary - Metal retains its name nonmetal ends -ide –Know the normal charges to combine -make neutral –Use roman numerals for charge on transition elements –Polyatomic ions memorize from Table 2.5 –Use ( ) for polyatomics, if more than 1 needed Nonmetal 1st -> molecule –Use prefixes!! Mono not used on 1st element –1st element retains its name, other ends -ide
Nomenclature H 1st = Acids –No oxygen, also ends -ide hydro ____ ic acid –Has oxygen, polyatomic ion (Table 2.5) -ate becomes ____ic acid -ite becomes ____ous acid H +1 used to balance polyatomic (-) charge