At the end of the last chapter, we discussed what changing the number of protons in an atom does to the element. Surprise, you have a different element altogether! Now we are going to look at changing the number of electrons to match the number of protons in the atom. After all, there has to be the same number of negative charges as positive charges or the atom will not be neutral.
The table has the elements organized into columns and rows. The seven horizontal rows correspond to the energy levels found outside an atom's nucleus. The row any element is located in tells you what the highest energy level is that will be accepting electrons. For example, calcium, Ca, is located in the fourth row from the top of the table, so the highest energy level that contains electrons in calcium is the fourth energy level.
But how do energy levels relate to the Periodic Table? Let's find out.