How are orbitals related to energy levels

1. How are orbitals related to energy levels • The principal quantum number, n, tells us: • The energy level the orbital is in • # of types of orbitals (the # of sublevels each energy level has) • The total number of actual orbitals in the energy level

2. Example If n=2 • We are referring to the 2nd energy level • There are two types of orbitals (or sublevels) s, p • There are 22 = 4 actual # of orbitals s, px,py,pz = 4 • We can now use orbital box diagrams to relate energy levels with orbitals

3. Rules to follow • Aufbau’s Principle – electrons will occupy orbitals having the lowest energy FIRST and then in order of increasing energy • Pauli’s Exclusion Principle – an orbital can be empty, have one or AT MOST have two electrons • Hund’s Rule – electrons in the same sublevel will not occupy the same orbital until all the orbitals in the same sublevel have been at least half filled • Spin – two electrons that occupy the same orbital always spin in opposite directions