Properties and Changes of Matter

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Properties and Changes of Matter
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• Matter is anything that has mass and takes up
  space (volume).

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A Common Classification Scheme
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(1) Substance

• matter with uniform and unchanging composition
  (PURE).
• constant properties throughout

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• Elements
• A substance that can not be broken down into
  simpler substances by a physical or chemical
  means.
• consists of atoms with the same atomic number

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• Examples of elements
• metal
• elements that are to the left of the bold-black
  zig-zag line
• usually solids, good conductors, shiny, ductile
  and malleable
• nonmetal
• elements that are to the right of the bold-black
  zig-zag line
• most are gases, dull and brittle solids, poor
  conductors

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• Examples of elements
• metalloids
• includes the elements Boron, Silicon, Germanium,
  Arsenic, Antimony, Tellurium
• demonstrate a mixture of metallic and nonmetallic
  properties

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Periodic Table of Elements

• In 1869, Dmitri Mendeleev devised a chart that
  organized all of the elements known at the time
  into rows and columns based on their similarities
  and their masses. The table is called the
  periodic table because the pattern of similar
  properties repeats as you move from period to
  period.....Today, this is based on atomic number
  not mass.

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• Brilliant Aspects
• (1) He left blank areas that could accommodate
  undiscovered elements.
• (2) The properties of undiscovered elements could
  be predicted.
• Periods
• a horizontal row of elements

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• Groups (Families)
• a vertical column of elements that is also called
  a family because they have similar properties.
• Group 1 alkali metals
• Group 2 alkaline earth metals
• Group 17 halogens
• Group 18 noble gases

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• Compound
• a chemical combination of two or more different
  elements
• can be broken down into simpler substances by
  chemical means
• has different properties from the elements that
  make it up

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• Classification of Compounds
• (1)Binary Compounds compounds containing 2
  elements chemically combined.
• Example NaCl ( 2 capital letters)
• (2)Ternary Compounds compounds that contain
  more than 2 elements
• Example MgCO3 (3 or more capital letters)

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(2) Mixture

• combination of two or more pure substances
• each component maintains its own properties
• components can be physically separated

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• Homogeneous Mixture
• has constant composition throughout and always
  has a single phase
• Examples Solutions such as kool-aid, brass,
  bronze, other alloys, air
• Heterogeneous Mixture
• does not blend smoothly throughout
• often called a mechanical mixture
• Examples fresh squeezed orange juice, pizza,
  vegetable soup, Italian dressing