The Exclusion Principle and the Periodic Table

Write the electron configuration for potassium.

Free Compression Lab Continuation: We have seen that with four molecules in our gas box, a 50/50 split (2 on each side) has the most microstates but we do observe other configurations (all on one side for example) Just like with our coins, this would be true with real gas molecules too Why do we not see other options in our everyday world: we never see significant numbers of gas molecules on one side of a room! Something must happen when we increase the number of molecules from four to the 1028 in this room. To understand why, we will be looking at the fraction of the time that the split is within 10% of 50/50, i.e. “What fraction of the time is the number of molecules on the left between 40% and 60% of all of the molecules Let’s start looking at the 40% - 60% range in our 4-molecule gas o 10% of 4 is 0.4 o So we are interested in the range 2 +- 0.4 on the left o Clearly cannot have 0.4 of a molecule o i.e. only the 50/50 configuration o This make the 4-molecule configuration a bit weird The probability that we observe between 40% and 60% of the molecules on the left is just the probability of 2 on the left: 0.375 Where 40% - 60% is actually a range: o 10% of 10 is 1 o So we are interested in the fraction of the time where there are between 4 and 6 (inclusive) molecules on the left o In order to do this we need o The number of microstates corresponding to the macrostates