Notes #5: History of the Atom (pt 5) - Orbitals! WCHS Chemistry **NEED YOUR PERIODIC TABLES!**

ELECTRON ORBITALS What Bohr didn’t figure out was that each region of his “orbits” was broken down into smaller regions → ORBITALS! However, Bohr was correct on: Low energy closest to the nucleus High energy the farther out you go

Orbitals # of varieties Pictures ORBITAL SHAPES Orbitals # of varieties Pictures DON’T NEED TO KNOW! S 1 p 3 d 5 f 7

S & p orbitals animation Scandium Energy Level # of sublevels Orbital Types # of Orbitals Max # of e-s 1 1 s(1) 1 2 2 2 s(1)p(3) 4 8 3 3 s(1)p(3)d(5) 9 18 4 4 s(1)p(3)d(5)f(7) 16 32 S & p orbitals animation Scandium

WE NEED A NEW MODEL Aufbau Principle Start at the lowest energy level and fill up from there. (lazy electrons) NOTICE 4s!!! Hund’s Rule Fill each orbital before doubling up. (electrons don’t share)

Rules for Writing e- Configuration: Big # = Energy Level When filling orbital: One e- in each before doubling up Double up before moving up! Rules for Writing e- Configuration: Big # = Energy Level Little # = # of electrons in that sublevel

AUFBAU’S PRINCIPLE = Start at lowest energy level and fill up from there CAN YOU THINK OF A SITUATION THAT VIOLATES THIS PRINCIPLE? Excited State!