CHEM 1211 Lecture 4: Chapter2Student-2
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An atom is the smallest identifiable unit of an element. There are approximately 90 different naturally occurring element and over 20 synthetic elements that scientists have succeeded to make. Early visionaries: leucippus and his student democritus (460-370 b. c. Erroneous plato and aristotle matter had no small parts and different. Substances were composed of fire, air, earth, water. Intellectual thought was delayed almost 2000 years: early 1800"s john dalton (1766-1844) modern atomic theory (using ideas from leucippus and democritus. (a) (b) (c) (d) (e) Later we found out that letters ( b ) and ( c ) are not correct. What were the three most important laws that led to the modern atomic. Theory: law of conservation of mass (antoine lavoisier) In a chemical reaction, matter is neither created nor destroyed. (consistent with idea that matter is composed of small indestructible particles): the law of definite proportions (joseph proust)
