2.3: the periodic table

groups in the periodic table

• metals
  • conductors (to varying degrees)
  • lose electrons
  • malleable and ductile (flexible)
  • shiny/lustrous
• nonmetals
  • nonconductors
  • gain electrons
  • brittle (not malleable or ductile)
  • dull in texture/appearance
• metalloids/semi-conductors
  • bridge metals and non-metals, have qualities of both

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metal groups

• alkali metals
  • have one valence electron (electron in the highest occupied energy level)
  • most reactive metal group
• alkaline earth metals
  • 2 valence electrons
  • less reactive than alkali metals
  • 2nd most reactive group
• transition metals
  • multiple charges on ions
  • some references refer to these elements as “post-transition metals”
  • don’t behave consistently

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nonmetal groups

• halogens
  • 7 valence electrons
  • most reactive nonmetal group
• noble gases
  • 8 valence electrons (highest occupied energy level is full)
  • most stable group

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the periodic table

• periodic table: a systematic organization of the elements
• elements are arranged in order of atomic number
• the rows of the periodic table (left to right) are called periods
• the columns of the periodic table (top to bottom) are called groups or families
• elements in the same group have similar properties
• periodicity
• periodic = cyclical
• there is a repeating pattern of reactivities and other properties as we move across the periodic table
• metals are on the left side of the periodic table, whereas non-metals are on the right side of the table (except for Hydrogen). metalloids are near the right side but not on the far right.

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