Vocabulary Quantum Amount of energy required to move an electron from it’s present energy level to another. Like gravity the energy needed to change levels gets less the farther away from the nucleus you get. Ex. See Pg 363 There is no fixed orbit like in the Bohr model. Instead, electron clouds provide a 90% probability that you’ll find an electron somewhere in the cloud.

Electron Clouds

Vocabulary Principle Quantum Number N = 1, 2, 3, 4, etc… increases in energy  N is the number of sublevels. Ex. N=1, there is one sublevel Regions where electrons can be found are called orbitals.

Vocabulary Atomic Orbitals s, p, d, f s orbitals are spherical. p orbitals are dumbbell shaped in X, Y and Z planes d orbitals are cloverleaf shaped in X, Y and Z planes f orbitals are really complicated and difficult to visualize

Vocabulary Principal Energy Level # of sublevels Type of sublevelN 2 = # of orbitals n = 111s (1)1 2 = 1 n = 222s (1), 2p (3)2 2 = 4 n = 333s (1), 3p (3), 3d (5)3 2 = 9 n = 444s (1), 4p (3), 4d (5), 4f (7) 4 2 = 16

Total possible number of electrons in a principal energy level (n) # of electrons = 2n 2 Ex. 2 * (1) 2 = 2, so in the 1 st principal energy level there can only be 2 e’s. Ex. 2 * (2) 2 = 8, so in the 2 nd principal energy level there can only be 8 e’s.

Vocabulary Aufbau Principle e - ’s enter orbitals of the lowest energy 1 st. Orbitals within a sublevel are always equal in energy. S is always the lowest energy sublevel. Beyond the 2 nd energy level, there are interesting changes that happen with the overlapping of principle energy levels.

Aufbau orbital filling order

Vocabulary Pauli Exclusion Principle An atomic orbital may describe at most 2 e - ’s and they will have opposite spins. Ex.  or  Magnets come from the aligning magnetic domains, coming from electron spins

Vocabulary Hund’s Rule When you’re filling orbitals, e - ’s don’t want to be paired unless they have to. Like a family filling rooms. If there is an empty room, then the electrons will go there first.

Let’s Practice Sodium (Na) Electron configuration: 1s 2 2s 2 2p 6 3s 1 Now draw the Aufbau Diagram of Sodium (Na). Use diagram on page 367 in your book to set it up.

Let’s Practice Chlorine (Cl) Electron configuration: 1s 2 2s 2 2p 6 3s 2 3p 5 Now draw the Aufbau Diagram of Chlorine (Cl). Use diagram on page 367 in your book to set it up.