Rules of Electron Location and Orbital Filling Order Quantum Numbers Rules of Electron Location and Orbital Filling Order

Heisenberg Uncertainty Principle It is impossible to determine both the position and the velocity of an electron at the same time.

Aufbau Principle An electron occupies the lowest energy level available.

Pauli Exclusion Principle No 2 electrons in the same atom can have the same 4 identical quantum numbers. In other words, no two electrons can be in the same place at the same time.

Hund’s Rule Orbitals of equal energy are each occupied by ONE electron before any orbital is occupied by a SECOND electron All electrons in a single occupied orbital must have the same spin.

QUANTUM THEORY: shows how the electron determines an atom's behavior and properties 4 Quantum Numbers must be used to describe the position of the electrons in an atom n, l, m, s are the "numbers" Each electron has a different set (just like each locker out in the hall has a different combination)

Principal Quantum Number Symbol = n Represents the main energy level of the electron Range = 1- 7 Equation: 2n2 - shows how many electrons can be in each energy level (e.g. level 3: 2(3)2 = 18 e-'s) Ex. = 3s Principal Quantum number = 3

Angular Momentum Quantum Number Symbol = l (small letter L) Identifies the shape of the orbital (also called sublevel) Range = 0 – n-1 (whole number) Shapes: 0 = s (sphere) 1 = p (petal) (peanut) 2 = d (double petal) 3 = f (flower) (double peanut)

Shapes of the Charge Clouds s for "Sphere": simplest shape, or shape of the simplest atoms like hydrogen and helium Electrons don't interfere with, or block, each other from the pull of the nucleus - ball shape Each energy level has an "s" orbital at the lowest energy within that level

Shapes of the Charge Clouds p for "Peanut": more complex shape that occurs at energy levels 2 and above

Shapes of the Charge Clouds d for "Double Peanut": complex shape occurring at energy levels 3 and above The arrangement of these orbitals allows for "s" and "p" orbitals to fit closer to the middle/nucleus

Shapes of the Charge Clouds f for "Flower": 7 bizarre-shaped orbitals for electrons of very large atoms electrons filling these orbitals are weakly attached to the atom because they are so far away from the pull of the nucleus

Magnetic Quantum Number Symbol = m Represents the orientation of the orbital around the nucleus m can be from –l to +l Each line holds 2 electrons ___ = s ___ ___ ___ = p -1 0 +1

Magnetic Quantum Number (cont.) ___ ___ ___ ___ ___ = d -2 -1 0 +1 +2 ___ ___ ___ ___ ___ ___ ___ = f -3 -2 -1 0 +1 +2 +3

Spin Quantum Number 2 Spin States Clockwise spin = +1/2 (upward arrow) Counterclockwise spin = -1/2 (downward arrow) A Single orbital can hold two electrons, but they must have opposite spins