General Rules Pauli Exclusion Principle Each orbital can hold TWO electrons with opposite spins. Wolfgang Pauli
General Rules Aufbau Principle Electrons fill the lowest energy orbitals first. Lazy Tenant Rule Energy 6d 5f 7s 6p 5d 4f 6s 5p 4d 5s 4p 3d 4s 3p 3s 2p 2s 7s 6s 5s 4s 3s 6p 5p 4p 3p 2p 6d 5d 4d 3d 5f 4f 2s 1s 1s
General Rules Hund s Rule Within a sublevel, place one electron per orbital before pairing them. Empty Bus Seat Rule WRONG RIGHT
Notation 8 O 15.9994 Orbital Diagram O 8e - 1s 2s 2p Electron Configuration 1s 2 2s 2 2p 4
Notation 16 S 32.066 Longhand Configuration S 16e - 1s 2 2s 2 2p 6 3s 2 3p 4 Core Electrons Valence Electrons Shorthand Configuration S 16e - [Ne] 3s 2 3p 4
Periodic Patterns 1 2 3 4 5 6 7 s 1s 2s 3s 4s 5s 6s 7s d (n-1) 3d 4d 5d 6d p 2p 3p 4p 5p 6p 7p 1s f (n-2) 6 7 5f 4f
Periodic Patterns Period # energy level (subtract for d & f) A/B Group # total # of valence e - Column within sublevel block # of e - in sublevel
Periodic Patterns Example - Hydrogen 1 2 3 4 5 6 7 1s 1 1st column of s-block 1st Period s-block
Periodic Patterns Shorthand Configuration Core electrons: Go up one row and over to the Noble Gas. Valence electrons: On the next row, fill in the # of e - in each sublevel. 1 2 3 4 5 6 7
Periodic Patterns 32 Ge 72.61 Example - Germanium 1 2 3 4 5 6 7 [Ar] 4s 2 3d 10 4p 2
Stability 1 2 3 4 5 6 7 Full energy level Full sublevel (s, p, d, f) Half-full sublevel
The Octet Rule Atoms tend to gain, lose, or share electrons until they have eight valence electrons. This fills the valence shell and tends to give the atom the stability of the inert gasses. 8 ONLY s- and p-orbitals are valence electrons.
Stability Electron Configuration Exceptions Copper EXPECT: [Ar] 4s 2 3d 9 ACTUALLY: [Ar] 4s 1 3d 10 Copper gains stability with a full d-sublevel. When copper loses one electron it becomes more stable with Cu+ : [Ar] 3d10
Stability Electron Configuration Exceptions Chromium EXPECT: [Ar] 4s 2 3d 4 ACTUALLY: [Ar] 4s 1 3d 5 Chromium gains stability with a half-full d-sublevel.
Electron Filling in Periodic Table s s 1 p 2 3 d 4 K 4s 1 Ca 4s 2 Sc 3d 1 Ti 3d 2 V 3d 3 Cr 3d 45 Mn 3d 5 Fe 3d 6 Co 3d 7 Ni 3d 8 Cu 3d 9 3d 10 Zn 3d 10 Ga 4p 1 Ge 4p 2 As 4p 3 Se 4p 4 Br 4p 5 Kr 4p 6 Energy n = 4 n = 3 n = 2 n = 1 4f 4d 4p 3d 4s 3p 3s 2p 2s 1s Cr 4s 1 3d 5 4s Cu 4s 1 3d 10 3d Cr 4s 1 3d 5 Cu 4s 1 3d 10 4s 3d
Stability Ion Formation Atoms gain or lose electrons to become more stable. Isoelectronic with the Noble Gases. 1 2 3 4 5 6 7
Stability Ion Electron Configuration Write the e - configuration for the closest Noble Gas EX: Oxygen ion O 2- Ne O 2-10e - [He] 2s 2 2p 6
Orbital Diagrams for Nickel 28 Ni 58.6934 1s 2 2 6 2 6 2 8 2s 2p 3s 3p 4s 3d Excited State 1s 2s 2p 3s 3p 4s 3d 2 2 6 2 6 1 9 Pauli Exclusion 1s 2s 2p 3s 3p 4s 3d Hund s Rule 1s 2s 2p 3s 3p 4s 3d
First Four Energy Levels n = 4 n = 3 Energy n = 2 n = 1
Sublevels Sublevel designation Four sublevels 4s 4p 4d 4f Principal level 4 Three sublevels 3s 3p 3d Principal level 3 Two sublevels 2s 2p Principal level 2 Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 334 One sublevel 1s Principal level 1
Principal Level 2 Divided 2s sublevel 2p sublevel 2s 2p x 2p y 2p z Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 334
Sublevels Four sublevels Three sublevels Two sublevels One sublevel Principal level 1 Principal level 3 Principal level 2 Principal level 4 Energy n = 4 n = 3 4f 4d 4p 3d 4s 3p 3s 2p n = 2 2s n = 1 1s