The Periodic Pattern

The pattern of electron orbits (expressed via Mandeleev's periodic table) is a pattern of grouping, which can be explained with Bohr's atomic model as orbital shells.

• In level n=1, there is one set of orbits.
  • 2 electrons can exist in the (1S) orbits
• In level n=2, there are two sets of orbits.
  • 2 electrons in the (2S) orbits
  • 6 electrons in the (2P) orbits
• In level n=3, there are two sets of orbits.
  • 2 electrons in the (3S) orbits
  • 6 electrons in the (3P) orbits
• In level n=4, there are three sets of orbits.
  • 2 electrons in the (4S) orbits
  • 6 electrons in the (4P) orbits
  • 10 electrons in the (4D) orbits
• In level n=5, there are three sets of orbits.
  • 2 electrons in the (5S) orbits
  • 6 electrons in the (5P) orbits
  • 10 electrons in the (5D) orbits
• In level n=6, there are four sets of orbits.
  • 2 electrons in the (6S) orbits
  • 6 electrons in the (6P) orbits
  • 10 electrons in the (6D) orbits
  • 14 electrons in the (6F) orbits
• In level n=7, there are four sets of orbits.
  • 2 electrons in the (7S) orbits
  • 6 electrons in the (7P) orbits
  • 10 electrons in the (7D) orbits
  • 14 electrons in the (7F) orbits

In level n=7, there are four sets of orbits, but these atoms are extremely large and quickly become unstable. These elements can be produced in a lab, but they break apart rather quickly. The n=7 level has the same pattern as the n=6 level (SPDF). The elements with filled outer shells (all shells associated with some n) are the noble gases. See Table 3.6.3 for a few examples. Notice that the electrons do not necessarily always fill the shells in the order which you would expect. There are other factors which must be considered. (If you want to know this information, take a chemistry course - it'll be fun!)