Presentation on theme: "Thales (600 B.C.) Water Xenophanes (500 B.C.) EarthWater."— Presentation transcript:
Thales (600 B.C.) Water
Xenophanes (500 B.C.) EarthWater
Empedocles (440 B.C.) Four elements Earth Water Air Fire (more commonly called dirt)
Two Forces shape matter Love & Strife
Democritus Athens, Greece 400 B.C.
Since atomos is the Greek word for indivisible I shall call these particles atoms. Atoms cannot be destroyed, so there is conservation of matter. The smallest particles of matter are indivisible.
Aristotle Athens, Greece 340 B.C. Aristotle studied under Plato who also had opinions on chemistry. However, Aristotle had the most influence on the history of chemistry. Besides chemistry, he also tackled physics, biology, psychology, and logic.
Its ironic that the theories of Aristotle which were most accepted were also the most incorrect. His theories that were most correct were mostly ignored. For example, he correctly classified dolphins as mammals and not fish. It took 2,000 years for biologists to accept this. For example, he proposed and embraced the mystical fifth element. It took chemists 2,000 years to recognize that there was no mystical fifth element.
First Table of the Elements Hot Dry Cold Wet
Fifth Element Quintessence Philosophers stone
Fifth Element makes up the celestial bodies Gold is the perfect metal. All other metals are less perfect. The fifth element is so divine that it can turn the lesser (more base) metals into gold.
Elixir of life (a fountain of youth) Fifth Element
Matter does not consist of atoms Democritus said atoms cannot be divided. You cannot place restraints on the gods. Democritus Disagree with Democritus
Antoine Laurent Lavoisier France 1793 Lavoisier has been called the father of modern chemistry. Started a system of chemical nomenclature that used ide, -ic & - ous endings. Examples: Sodium chloride, Ferric oxide and Ferrous oxide
Antoine married the daughter of the tax collector, which helped him pay for his expensive laboratory. Marie acted as a skilled lab assistant, translator of English science publications, and illustrator for Lavoisiers experiments
Lavoisier When heated mercury turned red and absorbed 1/5 of the air The amount of active air consumed was the same as the amount of active air released later.
non-active Air Active Air Room Air Azote Oxygen generate acids Sulfuric acid Lived for a while Lived longer Died quickly S + O 2 SO 2 2SO 2 + O 2 2 SO 3 SO 3 + H 2 O H 2 SO 4
Table of the Elements (33) Antimony Arsenic Bismuth Cobalt Copper Gold Iron Lead Manganese Mercury Molybdena Nickel Platina Silver Tin Tungstein Zinc Oxygen Azote Hydrogen Sulphur Phosphorus Charcoal Muriatic radical Fluoric radical Boracic radical Lime Magnesia Barytes Argill Silex Argill (clay or alum=potassium aluminum sulfate) Silex (silicon dioxide = quartz Magnesia (epsom salts=magnesium sulfate) Lime = calcium oxide
John Dalton England 1796
Elements are composed of minute, indivisible particles called atoms
4. Chemical compounds are formed by the union of two or more atoms of different elements.
5. Atoms combine to form compounds in simple ratios, such as 1:1, 1:2, 2:2, 1:3, and so forth.
For example, if we decomposed 100 grams of water using electricity, we always get this proportion of mass. 88.8% 88.8 grams Oxygen 11.2% 11.2 grams Hydrogen
6. Atoms of two elements may combine in different ratios to form more than one compound. We call this: The Law of Multiple Proportions
Daltons Elements Arranged from light to heavy by their relative weights
Johan Jacob Berzelius from Sweden
Older elements take the symbol from their Latin name. Fe comes from ferrum not iron. Instead of G for gold he wants Au from aurum. Instead of S for Silver he wants Ag from argentum. Newer symbols come from English names. O comes from oxygen experiments over a ten-year period to determine accurate atomic masses for all the elements now known. Berzelius Symbols for Elements
John Newlands England 1867 Researchers had already began to arrange and classify elements: Metals vs. non-metals In tables of increasing atomic weight John Newlands from England had a different way to arrange elements.
Chlorine, bromine & iodine violently corrosive form acids Lithium, sodium, potassium Unite violently with oxygen or water Oxides form caustic aqueous solutions Every eighth element have similar characteristics Li Be B C N O F Na Mg Al Si P S Cl K Ca ? ? As Se Br Certain elements resembled one another in behavior. I call this the Law of Octaves
Li Be B C N O F Na Mg Al Si P S Cl K Ca ? ? As Se Br I call this the Law of Octaves because of its similarity to musical octaves Lightest to heaviest. Li Be B C N O F Na Mg Al Si P S Cl K Ca ? ? As Se Br ABCDEFGABCDEFGABCDEFGABCDEFGABCDEFGABCDEFG
Law of Octaves He presented his theory to the England Chemical Society and was laughed at. They said to arrange it alphabetically.
Dmitri Ivanovich Mendeleev Russia 1871
Periodic Law Like Newlands, he used the lithium, sodium, and potassium plus the chlorine family as guide posts He also saw a periodic repeating of characteristics. However on the third period, he thought there were more than the seven elements that Newlands listed.