Energy Levels & Orbitals

The Hydrogen Orbitals Orbitals do not have sharp boundaries.

The Hydrogen Orbitals Hydrogen has discrete energy levels. Called principal energy levels Labeled with whole numbers photon - An elementary particle, the quantum of the electromagnetic interaction and the basic unit of light. In other words a photon is a little packet of energy which can carry light.

The Hydrogen Orbitals Each principal energy level is divided into sublevels. Labeled with numbers and letters Indicate the shape of the orbital

The Hydrogen Orbitals The s and p types of sublevel

The Hydrogen Orbitals Hydrogen Orbitals Why does an H atom have so many orbitals and only 1 electron? An orbital is a potential space for an electron. Atoms can have many potential orbitals.

The Wave Mechanical Model: Further Development Atoms Beyond Hydrogen The Bohr model was discarded because it does not apply to all atoms.

The Wave Mechanical Model: Further Development Pauli Exclusion Principle - an atomic orbital can hold a maximum of 2 electrons and those 2 electrons must have opposite spins

General Rules Pauli Exclusion Principle Each orbital can hold TWO electrons with opposite spins.

General Rules WRONG RIGHT Hund’s Rule Within a sublevel, place one e- per orbital before pairing them. “Empty Bus Seat Rule” WRONG RIGHT

General Rules Aufbau Principle Electrons fill the lowest energy orbitals first. “Lazy Tenant Rule”

Sublevel Orbitals s----------- p----------- d----------- f----------- 1 3 5 7

Electron Arrangements in the First 18 Atoms on the Periodic Table Classifying Electrons Valence electrons – electrons in the outermost (highest) principal energy level of an atom Core electrons – inner electrons Elements with the same valence electron arrangement show very similar chemical behavior.

1s2 2s2 2p4 O Notation 1s 2s 2p 8e- Orbital Notation Electron Configuration 1s2 2s2 2p4

S 16e- 1s2 2s2 2p6 3s2 3p4 S 16e- [Ne] 3s2 3p4 Notation Core Electrons Longhand Configuration S 16e- 1s2 2s2 2p6 3s2 3p4 Core Electrons Valence Electrons Shorthand Configuration S 16e- [Ne] 3s2 3p4

Electron Configurations and the Periodic Table Orbital filling and the periodic table

1 2 3 4 5 6 7 s p d (n-1) 6 7 f (n-2)

Periodic Patterns p s d (n-1) f (n-2) Shorthand Configuration Core e-: Go up one row and over to the Noble Gas. Valence e-: On the next row, fill in the # of e- in each sublevel. s d (n-1) f (n-2) p

Periodic Patterns Example - Germanium [Ar] 4s2 3d10 4p2

H atom Electron configuration – electron arrangement – 1s1 Orbital diagram – orbital is a box grouped by sublevel containing arrow(s) to represent electrons

He atom Electron configuration– 1s2 Orbital diagram

Li atom Electron configuration– 1s2 2s1 Orbital diagram

H He Li C N O F Energy Level Diagram Bohr Model Arbitrary Energy Scale 6s 6p 5d 4f Bohr Model 5s 5p 4d 4s 4p 3d Arbitrary Energy Scale 3s 3p 2s 2p 1s Electron Configuration NUCLEUS H He Li C N O F CLICK ON ELEMENT TO FILL IN CHARTS

Electron Configuration Energy Level Diagram Hydrogen 6s 6p 5d 4f Bohr Model 5s 5p 4d 4s 4p 3d Arbitrary Energy Scale 3s 3p N 2s 2p 1s Electron Configuration NUCLEUS H = 1s1 H He Li C N Al Ar F Fe La CLICK ON ELEMENT TO FILL IN CHARTS

Electron Configuration Energy Level Diagram Helium 6s 6p 5d 4f Bohr Model 5s 5p 4d 4s 4p 3d Arbitrary Energy Scale 3s 3p N 2s 2p 1s Electron Configuration NUCLEUS He = 1s2 H He Li C N Al Ar F Fe La CLICK ON ELEMENT TO FILL IN CHARTS

Electron Configuration Energy Level Diagram Lithium 6s 6p 5d 4f Bohr Model 5s 5p 4d 4s 4p 3d Arbitrary Energy Scale 3s 3p N 2s 2p 1s Electron Configuration NUCLEUS Li = 1s22s1 H He Li C N Al Ar F Fe La CLICK ON ELEMENT TO FILL IN CHARTS

Electron Configuration Energy Level Diagram Carbon 6s 6p 5d 4f Bohr Model 5s 5p 4d 4s 4p 3d Arbitrary Energy Scale 3s 3p N 2s 2p 1s Electron Configuration NUCLEUS C = 1s22s22p2 H He Li C N Al Ar F Fe La CLICK ON ELEMENT TO FILL IN CHARTS

Electron Configuration Energy Level Diagram Nitrogen 6s 6p 5d 4f Bohr Model 5s 5p 4d 4s 4p 3d Arbitrary Energy Scale 3s 3p N Hund’s Rule “maximum number of unpaired orbitals”. 2s 2p Electron Configuration 1s NUCLEUS N = 1s22s22p3 H He Li C N Al Ar F Fe La CLICK ON ELEMENT TO FILL IN CHARTS

Electron Configuration Energy Level Diagram Fluorine 6s 6p 5d 4f Bohr Model 5s 5p 4d 4s 4p 3d Arbitrary Energy Scale 3s 3p N 2s 2p Electron Configuration 1s NUCLEUS F = 1s22s22p5 H He Li C N Al Ar F Fe La CLICK ON ELEMENT TO FILL IN CHARTS

Electron Configuration Energy Level Diagram Aluminum 6s 6p 5d 4f Bohr Model 5s 5p 4d 4s 4p 3d Arbitrary Energy Scale 3s 3p N 2s 2p Electron Configuration 1s NUCLEUS Al = 1s22s22p63s23p1 H He Li C N Al Ar F Fe La CLICK ON ELEMENT TO FILL IN CHARTS

Electron Configuration Energy Level Diagram Argon 6s 6p 5d 4f Bohr Model 5s 5p 4d 4s 4p 3d Arbitrary Energy Scale 3s 3p N 2s 2p 1s Electron Configuration NUCLEUS Ar = 1s22s22p63s23p6 H He Li C N Al Ar F Fe La CLICK ON ELEMENT TO FILL IN CHARTS

Electron Configuration Energy Level Diagram Iron 6s 6p 5d 4f Bohr Model 5s 5p 4d 4s 4p 3d Arbitrary Energy Scale 3s 3p N 2s 2p 1s Electron Configuration NUCLEUS Fe = 1s22s22p63s23p64s23d6 H He Li C N Al Ar F Fe La CLICK ON ELEMENT TO FILL IN CHARTS

Electron Configuration Energy Level Diagram Lanthanum 6s 6p 5d 4f Bohr Model 5s 5p 4d 4s 4p 3d N Arbitrary Energy Scale 3s 3p 2s 2p 1s Electron Configuration NUCLEUS La = 1s22s22p63s23p64s23d6 4s23d104p65s24d105p66s25d1 H He Li C N Al O F Fe La CLICK ON ELEMENT TO FILL IN CHARTS

B. Electron Configurations and the Periodic Table Look at electron configurations for K through Kr

Electron Configurations and the Periodic Table

C. Periodic Patterns Period # A/B Group # Column within sublevel block energy level (subtract for d & f) A/B Group # total # of valence e- Column within sublevel block # of e- in sublevel

Atomic Properties and the Periodic Table Metals and Nonmetals Metals tend to lose electrons to form positive ions. Nonmetals tend to gain electrons to form negative ions.

Atomic Properties and the Periodic Table Atomic Size Size tends to increase down a column. Size tends to decrease across a row.

Atomic Properties and the Periodic Table Ionization Energies Ionization Energy – energy required to remove an electron from an individual atom (gas) Tends to decrease down a column Tends to increase across a row