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Each group is highlighted with a different color.
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Columns of the periodic table are called groups  .

 

Elements in the same group have similar chemical properties  to each other.

 

Groups are numbered from left to right using numbers 1-8.  The number of the group is the number of electrons in the valence shell  of the elements in the group.

(Note that the middle of the periodic table is not divided into groups.  For the purpose of this book, we will only be focusing on the 8 main groups)

  • Group 1 is red
  • Group 2 is orange
  • Group 3 is yellow
  • Group 4 is green
  • Group 5 is light blue
  • Group 7 is dark blue
  • Group 8 is purple