Orbitals and Electron Configurations Mrs Russotto

Review of Quantum Mechanical Model of Atom Atom is made up of nucleus – protons and neutrons Electrons in electron cloud outside nucleus called orbitals –Regions most likely to find electron Based on mathematical solution to Schrödinger’s wave equation

Atomic Orbitals s-orbital (1) - spheres p-orbitals (3) - dumbbells d-orbitals (5) – 4 clovers + 1 dumbbell with ring

Summary – p. 131 Principal energy level Number of sublevels Types of Orbitals n = 11s (1) n = 22s (1) and p (3) n = 33s (1), p (3), d (5) n = 44 s (1), p (3), d (5), f (7)

Check for Understanding How many energy sublevels are there in the third principal energy level? What is the maximum number of p-orbitals in a principal energy level?

Electron Configurations: An Electron’s Address Rules –aufbau principle – electrons occupy orbitals of lowest energy first (Fig 5.7 – p. 133) –Pauli exclusion principle – each orbital can hold a max of 2 electrons –Hund’s Rule – electrons occupy orbitals with the same energy individually first before pairing up

Energy Level Filling Diagram Use the diagram below to figure out the filling order of the orbitals

Orbital Filling Diagrams Sometimes called aufbau diagrams –show electrons with arrows –each orbital represented with a line

Electron Configurations electron configurations –write energy level and symbol for every sublevel occupied –shorthand of orbital filling diagrams abbreviated electron configurations –shortened electron configuration –use the symbol for the noble gas (Group 18) in the row above the element of interest –write the rest of the electron configuration as usually starting at row number for the element and “s” orbital in the energy level diagram

Periodic table (wide) - Wikipedia, the free encyclopedia