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The Evolution of our Atomic Theory. Ancient Greece to Present Day. Ancient Greek philosopher Coined the term atom(from the greek atomos -indivisible) Matter is made up of small particles that cannot be divided
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The Evolution of our Atomic Theory Ancient Greece to Present Day
Ancient Greek philosopher • Coined the term atom(from the greekatomos-indivisible) • Matter is made up of small particles that cannot be divided • Atoms differed in size and shape and were able to combine in different combinations
Experimented with gases • Published his atomic theory in 1808 • 6 Important Points: • Different elements have different atoms • Atoms of one element are identical • Different elements have different properties • Atoms are rearranged by chemical reactions • Atoms combine to form compounds • Compounds have definite types, numbers and proportions of elements • Father of Modern Chemistry
English Physicist and Chemist • Identified the electron as having a negative charge • Atoms are neutral • Electrons are embedded in a positive sphere • Chocolate Chip Cookie Dough Model
Gold Foil Experiment • Bombarded Gold foil with Alpha particles(positively charged lightweight atoms) • Some went straight through, while some bounced backwards • Showed atom is made of empty space and a strong positive center(THE NUCLEUS!) • Electrons were located around the nucleus, but he didn’t know where
Danish Physicist • Used Rutherford’s results to describe location of electrons • Electrons move around nucleus in fixed orbits(orbitals) • Still used today to describe atom
Combination of de Broglie and Schrodinger’s ideas • Shows that electrons have a certain probability to be in specific energy levels(orbitals) • Chadwick later discovered the third sub-atomic particle • The neutron—neutral charge