Lecture : Gen Chem Lecture-2
Document Summary
Atoms and the atomic theory: early discoveries and the atomic theory. Proust 1799- law of constant composition: dalton 1803-1888- atomic. Total mass of substance is constant before and after reaction. All sample of a compound has same composition-same proportion in masses of its constituents. Each element is composed of small particles called atoms. Atoms are neither created nor destroyed in chemical reactions. All atoms of a given element are identical and differ from all other elements. Compounds are formed when atoms of more than one element combine in simple numerical ratios. If two elements form more than a single compound, the masses of one element combined with a fixed mass of the second are in ratio of small whole numbers. Thomson concluded that crs are negatively charged fundamental particle of matter found in all atoms. Robert millikan showed ionized oil drops can be balanced against the pull of gravity by an electric field.
