Electronic structure and the periodic table
As you have seen, there is a link between an atom's electronic structure and its position in the periodic table. You can work out an atom's electronic structure from its place in the periodic table.
The diagram shows a section of the periodic table, with the elements arranged as usual in the order of their atomic number, from 2 to 20. The red numbers below each chemical symbol show its electronic structure.
Moving across each period, you can see that the number of occupied energy levels is the same as the period number.
As you go across each period from left to right, an energy level gradually becomes filled with electrons. The highest occupied energy level contains just one electron on the left-hand side of the table. It is filled by the time you get to the right-hand side.
Moving down each group, you can see that the…