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Greek philosophers
led to fundamental substances called elements
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Democritus
said elements were composed of tiny particles that couldn't be further divided
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Robert Boyle
Showed matter is made up of atoms (from studies of air and gases) and elements were pure substances that couldn't be broken down any further
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Joesph Priestly
heated mercury 2 oxide and produced oxygen
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Antoine Lavoisier
showed oxygen was a key substance in combustion reactions and that in a combusion reaction, the mass of products = mass of reactants
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Law of Mass Conservation
Mass is neither created or destroyed
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Joesph Proust
- law of definite proportions
- dif samples of pure substances always contain the same proportions of elements by mass
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John Dalton
- Dalton's Atomic Theory
- -elements are made of tiny particles called atoms
- -atoms of the same element have the same mass (thought what made elements dif was their masses)
- -chemical combinations of elements only occur in whole # ratios
- -chemical reactions only rearrange the way the atoms are combined; the atoms themselves are unchanged
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law of multiple proportions
- -the same elements can combine in dif ways to form dif substances, whose mass ratios are small, whole # multiples of each other.
- -ex: CO, CO2= 2 times more O in CO2 than CO
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structure of atoms
electrons, protons, neutrons
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Dimitri Mendeleev
arranged elements in order of increasing atomic weight
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chemical bond
force that holds 2 atoms together- covalent or ionic
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covalent bond
sharing of e-s H2O
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ionic bond
transfer of e-s NaCl
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Structural formula
- shows how molecule put together
- H
- / \
- O O
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molecular compound
uses covalent bonds to form molecules
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polyatomic ion
charged molecule
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hydrate
- compound in which a certain # of h2o molecules are contained in the formula
- ex: CaCl2 * 6H2O
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Alkanes
hydrocarbons saturated w/ hydrogens
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