CHEM 001A Lecture Notes - Lecture 2: Cathode Ray Tube, Oil Drop Experiment, Cathode Ray
8 Mar 2018
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Review: significant figures rules: start at the left of the number and move right until you reach the first nonzero digit, count that digit and every digit to its right as significant. Substances: element, matter consisting of one kind of atom. Fixed composition: compound, matter consisting of two or more different kinds of atoms (elements) fixed. Composition: mixture, group of two or more substances that are physically intermingled. Experiment: examine cathode rays with electric and magnetic fields. Tho(cid:373)so(cid:374)"s model of the ato(cid:373: plum pudding model, e- distributed throughout diffuse, positively charged sphere. Atomic structure: the nucleus: rutherford"s (cid:894)ne(cid:449) )eala(cid:374)d(cid:895) gold foil experi(cid:373)e(cid:374)t, bombard a thin gold foil with parti(cid:272)les to test tho(cid:373)so(cid:374)"s (cid:373)odel of the ato(cid:373) Interpretation: by british physicist, ernest rutherford (1911: most particles went straight through foil implies atom mostly empty space, a few were scattered implies small nucleus, positive charge. The nuclear atom: nucleus has protons (+ charge) plus neutrons (neutral, distance is measures in picometers (pm)
