this is msj chem in this video i'll be taking a quick look at atomic orbitals and sublevels so we'll start by looking at the shapes of s orbitals and p orbitals before we do so here we have a definition an atomic orbital is a region of space where there is a high probability of finding an electron so starting with s orbitals which are spherical on the right we can see the shapes of a 1s orbital and a 2s orbital next we have p orbitals which are dumbbell shaped in the p sublevel there are three p orbitals which are labeled px py and pz the orientation of the orbitals is at 90 degrees to each other so to summarize s orbitals are spherical and p orbitals are dumbbell shaped so next we look at sublevels so each principal energy level is split into sublevels the first principal energy level which is labeled as n equals one has one sub level which is the one s sublevel the second principal energy level which is n equals 2 has two sub-levels they are the 2s and 2p sub-levels the third principal energy level which is n equals 3 has three sub-levels which are the 3s the 3p and the 3d sub levels and finally we have the fourth principal energy level which is n equals four and this has four sub levels they are the 4s the 4p the 4d and the 4f sublevels on the right we can see these sublevels arranged in order of energy with the lowest energy being the 1s sublevel and the highest energy being the 4p sublevel in the next video we'll look at how these sub levels are filled with electrons note that within the main energy level or principal energy level the order of energy is as follows so the s sublevel is the lowest energy and the f sublevel is the highest energy so for example the 4s sublevel is the lowest energy and the 4f sublevel is the highest energy so let's end the video with a summary in this table we have the principal energy level or main energy level with the number of sub-levels the number of electrons in each sub-level the number of orbitals and the total number of electrons in each main energy level so starting with n equals 1 which has a 1s sublevel this can hold a maximum of 2 electrons so the n equals 1 energy level has one orbital which can hold two electrons next we have n equals 2 which has 1 2s sublevel and 1 2p sublevel the 2s sublevel can hold 2 electrons and the 2p sublevel can hold 6 electrons the number of orbitals is 4 which can hold a total of 8 electrons moving on to n equals 3 which has a 3s a 3p and a 3d sub level the 3s sublevel can hold 2 electrons the 3p sublevel can hold 6 and the 3d sublevel can hold 10 electrons the total number of atomic orbitals is 9 which can hold 18 electrons and finally we have the n equals 4 energy level this has a 4s sublevel a 4p sub level a 4d sub level and a 4f sub level the 4s sub level can hold 2 electrons the 4p sublevel can hold 6. the 4d sublevel can hold 10 and the 4f sublevel can hold 14 electrons the total number of orbitals is 16 which can hold a maximum of 32 electrons so that's all from this video in the next video we look at the order of filling of these atomic orbitals