Section: Compounds & Molecules
Key Words: atom, element, molecule, compound, chemical bond, organic compound, monomer, polymer, carbon,
diatomic molecule, ionic compound, molecular compound, ion, hydrogen ion, hydroxide ion, dissociation, periodic
table, crystal
Essential Questions:
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What is a compound?
How are compounds named?
How are compounds made from carbon unique?
What are molecules made of and what are their properties?
How are compounds different from the elements from which they are formed?
How can you predict how atoms will combine to form a molecule?
How can ionic compounds break into pieces?
Matter – made up of pure substances

Combine in predictable ways to form compounds
Matter
pure substances
mixtures
elements
compounds
unique properties to
itself
unique properites to
each compound
created (combined)
Na - Sodium
Cl - Chlorine
-greenish poisonous gas
- soft silvery metal
reacts violently with
H2O
NaCl - Sodium Chloride
-colorless crystalline
solid
a combination of pure
substances that do not
chemically combine can physically separate
Homogeneous
Heterogeneous
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Compounds
 Two or more elements chemical combined
 Bonds hold compounds together
 Covalent
 Elements in compound share electrons
 Ionic
 One (or more) elements gives up electrons to another
 Alternating + or – atoms  ions (charged particles)
 Commonly called salts
 When placed in water, they break apart or “dissociate” into the ions
from which they were made
 Ions in water forma a solution
 Stored energy in bonds – makes them difficult to break
 Identified over 50 mill compounds today
 Most contain C
 Organic compounds (living)
 Found in living things
 Inorganic compounds (nonliving)
 Gases, sugars, etc. not living but contain carbon
Molecular
stucture
Molecules
Molecular
compounds
more than
one atom
more than
one atom
same
element
different
elements
H2, O2, N2
CO, HCl, H2O,
CO2, C6H12O6
diatomic - contains
only 2 atoms
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Molecules in water
 Make solution
 Molecules separate from each other
 Spread evenly throughout substance
 Break apart
 Produce ions
 Ex. HCl
+
 Breaks into H and CL ions
+
 H2O breaks to form H3O and OH ion