Atomic structure Part I
• Historic review
• Fundamental chemistry laws
• Dalton’s atomic theory
• Substructure of the atom
• Elements, isotopes, and ions
• The periodic table
Early History of Chemistry
~5000 B.C.
• Pottery, dyeing, early metallurgy
~1000 B.C.
• Processing of various natural metals copper, iron, silver, gold (ornaments,
weapons, etc.)
~400 B.C. Greeks
• Matter is composed of 4 fundamental elements: fire, earth, water and air.
• Democritus proposed that matter is made of indivisible particles called
atomos (atoms)
~100 A.D. - 1650 Alchemists (“alchemist” comes from Arabic)
• Greece, Egypt, Middle East ⇒ Europe
• In early stages, influenced by the Greeks that believed that matter strives
towards perfection, the alchemist sought to convert ("transmute") "lesser"
metals into "pure" metals such as gold
12 and 13 Centuries – A shift from alchemy
• Moving from traditional emphasis of transmutation towards moral, spiritual
and philosophical transmutation
Nicholas Flamel (of Harry Potter fame) (1330 - 1417?)
• Philosopher's stone
• Elixir of life but also promoting Christian morality and salvation
16th Century
• Alchemists are turning into serious scientists
• Less concern about monetary value (transmutation and conversion into gold)
• Discovering various elements and preparing various compounds
Paracelsus, Theophrastus Philippus Aureolus Bombastus von Hohenheim (1493-
1541)
• To Paracelsus, alchemy meant the discovery and synthesis of compounds for
medicinal use
• He tries to explain solids, liquids, and gases:
In every object there is:
• A first principal responsible for the solid state (Salts)
• A second principal responsible for its "fatty" state (Sulfur) • A third principal responsible for its smoky or fluid state
(Mercury)
17th Century
Robert Boyle (1627 – 1691) (considered first modern chemist)
• Gas Law: PV = constant
• Proposes that there are more than four elements
1774 Joseph Priestly isolated oxygen
Fundamental Chemistry Laws
Lavoisier (1789) Law of conservation of mass
• Mass is neither created nor destroyed
Proust (1799) Law of definite proportions
• A given compound always has the same proportion of elements by mass (by
atoms)
Eg. CCl4is always 1
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