Electron Configurations 3 Types Electron Configuration Notation Shorthand

Electron Configurations 3 Types • Electron Configuration Notation • Shorthand Notation • Orbital Notation

Symbols • Electrons: or superscripts • Orbitals: or ____ • Spin of electrons will be represented by the direction of the arrow

Each orbital can hold at most 2 electrons. Total=of Every s sub levels have only 1 orbital p sublevels have 3 orbitals 2 e =6 d sublevels have 5 orbitals = 10 f sublevels have 7 orbitals = 14

Key Terms • Ground State: refers to electrons having the lowest possible energy • Excited State: refers to electrons having gained energy. An excited electron will return to its ground state and when it does it will emit light. • Quantum numbers: specifies the properties and location of an electron

Quantum numbers • n refers to the energy level; n can be 1 -7 • l refers to the sublevel and describes the shape of the orbital. l can be 0 -3 with • 0 representing s shaped orbitals, • 1 representing p shaped orbitals, • 2 representing d shaped orbitals • 3 representing f shaped orbitals • m refers to magnetic quantum number • or refers to the spin of the electron

Electron Configuration…. . • …. refers to the distribution of electrons among orbitals of an atom. • …. is determined by distributing electrons among levels, sublevels and orbitals according to these rules: – Aufbau Principle – Pauli Exclusion Principle – Hund’s Rule

The Rules for Electron Configurations Aufbau Principle: • Electrons are added one at a time to the lowest energy orbitals until all electrons have been included. • “Lazy Tenant Rule”

Rules (cont’d): Pauli Exclusion Principle – Each orbital can hold at most 2 electrons; when the orbital holds 2 electrons they will have opposite spins.

Rules (cont’d) Hund’s Rule: each orbital of a sublevel must have at least one electron before adding a second electron – Within a sublevel, place one e- per orbital before pairing them. • “Empty Bus Seat Rule” WRONG RIGHT

Orbital Filling Order This diagram shows how the complex orbitals of large atoms overlap and fill “out of order. ” You should memorize the patterns shown in the diagram and be able to redraw it without looking at it.

To write the orbital notation for Vanadium: To write the electron configuration notation for Vanadium:

Electron configuration demonstrations • http: //intro. chem. okstate. edu/ Workshop. Folder/Electronconfn ew. html

Orbital Diagrams H 1 s l 2 s Electron Configuration 1 1 s 2 p

1. Write the orbital notation for silver. 2. Write the electron configuration for silver.

Orbital Diagrams

Orbital Diagrams

Orbital Diagrams • Your turn…. . • Practice on worksheet

Writing Electron Configurations H 1 s 1 He 1 s 2 Li 1 s 2 2 s 1 C 1 s 2 2 p 2 S 1 s 2 2 p 6 3 s 2 3 p 4

Exceptions to the Aufbau Principle • Recall that some orbitals are very close in energy. – This is especially true for large atoms having lots of d and f orbitals. – This causes certain orbitals to fill before one would normally expect. • Chromium and Copper illustrate the exceptions (page 153). – A certain amount of energy stability results from halffilled orbitals, and this accounts for the orbital filling order in Cr and Cu.

Exceptions Chromium • Instead of: – 1 s 2 2 p 6 3 s 2 3 p 6 4 s 2 3 d 4 – 1 s 2 2 p 6 3 s 2 3 p 6 4 s 1 3 d 5 Copper • Instead of: – 1 s 2 2 p 6 3 s 2 3 p 6 4 s 2 3 d 9 • 1 s 2 2 p 6 3 s 2 3 p 6 4 s 1 3 d 10

Periodic Table vs. Configurations Last electron filling. . . http: //www. uky. edu/~holler/html/orbitals_2. html

• The Periodic Table- e configuration

WOW! We sure covered a lot of territory! You have finished a very important, concept in Chemistry. CONGRATULATIONS!