ATOMIC STRUCTURE

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ATOMIC STRUCTURE
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DEFINITIONS p.31

• MATTER
• MASS
• Volume
• is the amount of space an object
  OCCUPIES
• No two pieces of matter can occupy the same space
  at the same time
• MATTER IS ANYTHING THAT HAS VOLUME AND MASS.

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• WEIGHT
• measure of pull of gravity on object
• WEIGHT CAN CHANGE/MASS IS CONSTANT
• further from center of earth the less weight

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Elements

• Definition p. 31
• Periodic Table of Elements
• Developed by Dmitri Mendeleev
• 114 confirmed elements discovered
• 92 naturally occurring
• Elements listed after 92 are man-made
• ?? Man-made elements

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Elements

• Fewer than 30 are important to living organisms
• 4 elements comprise 90 mass of organisms
• Oxygen
• Carbon
• Hydrogen
• nitrogen

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Four basic pieces of information foundon all
PERIODIC TABLES

• Element name
• Element symbol
• Atomic number
• Atomic mass

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How element symbols were selected

• First letter of name
• First and second letter of name
• First and any other letter of name
• Three letters of name (Latin)
• First letter of Latin name
• First and second letter of Latin name
• First and any other letter of Latin name

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element symbol practice

• http//www.funbrain.com/periodic/index.html

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ATOM

• Smallest particle of matter
• Named by Democritus (ancient Greek)
• ATOMOS
• unable to be cut

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ATOM STRUCTURE3 basic subatomic particles

• Proton positive charge p
• Neutron neutral charge n
• both are found in NUCLEUS core of atom
• positive charge due to presence of
  
  proton

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ATOM STRUCTURE

• Electron negative charge e-
• Located in energy levels (shells)
• Energy cloud
• 1st level maximum 2 e-
• 2nd level maximum 8 e-
• 3rd level maximum 18 e-

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ATOMIC NUMBER

• Determined by number of protons present
• Whole number
• sequential

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ATOMIC MASS

• Measured in atomic mass units
  amu
• One proton one atomic mass unit
  amu
• One neutron one amu
• Determined by the number of protons PLUS the
  number of neutrons present
• pnatomic mass

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ISOTOPE

• Is an atom of an element that has the same number
  of protons and electrons BUT DIFFERS in the
  number of NEUTRONS
• Are neutral
• Deuterium form of hydrogen
• Tritium form of hydrogen
• Tin has ten isotopes

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• Superscript
• small number written in upper corner
  of element symbol
• Upper left indicates atomic mass
• Subscript
• small number written in lower corner
  of element symbol
• lower left indicates atomic number

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CHEMICAL SYMBOL

• Represents single ELEMENT
• One symbol Single atom
• one is understood / not written
• Subscript written to the right indicates the
  number of atoms OF a element present