Periodic Table

11SCI - Chemical Reactions

Finn LeSueur


The Periodic Table

The periodic table is not just a random order of elements, it has logic and reason! It can be used to predict the structure and properties of elements.

But First, Electron Shells!

  • Electrons exist in shells around the atom.
  • Shell one can take two electrons, and shells two and three can take eight electrons.


  • A row is called a period.
  • Moving left to right on a period, the atomic radius decreases, and the electronegativity increases

Electronegativity: how hard it is to remove an electron


  • A column is called a group.
  • A group tends to have similar valence shell electron configurations, while increasing the number of shells as you descend.

Valence Shell: The outermost shell