Electron Configuration

Simple model of a potassium atom Electron Structure In a neutral atom, electrons = atomic number. Electrons are arranged into energy levels. Energy Level (shell) defines how far the electron is away from the nucleus. n = 1 n = 3 n = 4 More Energy Nucleus n = 2 Simple model of a potassium atom

Quantum Numbers 4 numbers that define the location and movement of the electrons.

Principle Quantum number (n) = Energy Level (shell) defines how far the electron is away from the nucleus.

Orbitals Four types: Shells are divided into subshells (orbitals). Orbital quantum number (l) – defines the shape of the sublevel (orbital). Four types: s (sharp) p (principal) d (diffuse) f (fundamental)

Magnetic quantum number (m l) – defines the orientation in space of the orbital. s, p, d, and f orbitals

Electron Spin Spin Quantum number (ms) – designates direction of electron spin. Each orbital can hold up to 2 electrons. Why only 2 in each orbital? Spin up Spin down

Electron Structure Orbitals s / 1 orbital / 2 e- p / 3 orbitals / 6 e- d / 5 orbitals / 10 e- f / 7 orbitals / 14 e-

Electron Orbitals Aufbau Principle: lowest energy level fills first Hund’s Rule: electrons fill each orbital before pairing up “Creepy Bus Guy Rule” Pauli Exclusion Principle: no two e- will have the same quantum numbers (one spins up, one spins down) Orbital diagrams

Electron Configurations 3p 3d 4d 5d 6d 2p 4p 5p 6p 7p 4f 5f 1st row 2nd row 3rd row 4th row 5th row 6th row 7th row Row number – 1 Row number – 2

Lewis Dot Diagrams Electron Dot Diagram – shows the valence electrons of an atom as dots. Distribute dots around atomic symbol to represent valence electrons. Should never have more than 8 dots (octed). Helium will only have 2 dots (duet).

Noble Gas Configuration Find your element. Find the noble gas (Group 8A) before your element. Write the noble gas in brackets. Add electrons to the noble gas until you reach your element.