The ground state electron configuration is just the distribution of electrons, 1s, 2s, 2p, 3s, and so on, within orbitals using the Aufbau principle. Aufbau means "build up" in German. The Aufbau principle itself says, starting from 1s, electrons fill lower energy orbitals before moving to higher energy orbitals. When we talk about the condensed electron configuration, this is just a quicker way of writing it out. Here we'd say we start at the last noble gas before the desired element.
If we look at our periodic table, we break it up into different blocks. We have our s block, our p block, our d block, and our f block. Organic chemistry is really concerned with our non-metals. So for the most part, you're not going to deal with d blocks and f blocks. And if we take a look here at this periodic table, we start out with hydrogen here, which is 1s1. Helium would be 1s2, because we're dealing with our second electron. We get to our third electron, the 1s2 is filled, so we move on to 2s 1. This will be 1s22s2, which is why we go to 2p1. Continuing, this will be 3s, so this will be 1s2 2s2 2p6 3s1, eventually getting us over here, where this would end with 3p1.
Looking at this pattern, let's see what we can do in terms of this example. We'd say write the ground state and condensed electron configurations for the following element, phosphorus. Here is phosphorus right here. It tells us its atomic number, z, is 15, so it has 15 electrons. So following the pattern that we just saw, in this spot here that I circled, this would be 1s2 2s2 2p6 3s23p1. And all we got to do is count to phosphorus. So that would be for the ground state, it'd be 1s2 2s2 2p6 3s2 3p3, because it's 3p1, 3p2, 3p3. If you add up all the electrons that we have here, it would add up to 15, which is equal to the atomic number.
Now the last noble gas we pass before we get to phosphorus is neon. So neon is the element right here. So its condensed electron configuration would start out with the noble gas neon, and then we'd have 3s2 3p3. So this will represent our ground state and condensed electron configuration for the phosphorus atom.
