LOCATING MAIN GROUP ELEMENTS ON THE PERIODIC TABLE

Given the electron configuration or noble gas configuration for an element, it is possible to determine its location on the Periodic Table without actually looking at a Periodic Table.

* To tell which period this element is in...
~  find the highest occupied energy level for this element
You can do this by...
~  finding the largest coefficient number
The largest coefficient number is the number of the period where the element is located.

* To tell which "block" this element is in...  (like "s" block, "p" block, "d" block, etc)
~  find the highest occupied sublevel for this element
You can do this by...
~  finding the last lowercase letter written
The last lowercase letter written in the configuration is the "block" where the element is located.

* To tell which group this element is in...
~  find the highest occupied energy level for this element
You can do this by...
~  finding the largest coefficient number
Then...
~  add up the exponents of the largest coefficient number
This gives you the number of valence electrons in the element.
You will then know that 1 valence electron indicates that the element is in Group 1, 2 valence electrons indicates that the element is in Group 2, 3 valence electrons indicates that the element is in Group 13, 4 valence electrons indicates that the element is in Group 14, 5 valence electrons indicates that the element is in Group 15, 6 valence electrons indicates that the element is in Group 16, 7 valence electrons indicates that the element is in Group 17, and 8 valence electrons indicates that the element is in Group 18.

Look at the following example.

EXAMPLE:                [Ar] 4s2 3d10 4p5

It is possible to tell the period, group, and "block" where this element is located.
*  Period --  largest coefficient number is 4, so element is in Period 4
*  Block--  last lowercase letter written is "p", so element is in "p" block
*  Group--  largest coefficient number is 4...  2 electrons in 4s, 5 electrons in 4p -->  total of 7 valence electrons,
so this element is in Group 17.