ORGANIC CHEMISTRY 3540

FUNCTION FOLLOWS FORM

ATOMIC STRUCTURE

ORBITALS

ELECTRON CONFIGURATION

IONIC & COVALENT BONDS

LEWIS STRUCTURES

ATOMIC STRUCTURE

NUCLEUS

PROTONS

ATOMIC NUMBER (Z)

NEUTRONS

MASS NUMBER (A)

ATOMIC WEIGHT

ELECTRONS

ORBITALS (QUANTUM MECHANICS, WAVE EQUATION, WAVE FUNCTION = ORBITAL)

ORBITAL IS THE ENERGY STATE OF AN ELECTRON

WHAT WE SKETCH IS:

• REGION IN SPACE WHERE CHANCE OF FINDING AN ELECTRON IS HIGH
• REGION IN SPACE WHERE WAVE DENSITY IS HIGH
  • s, p, d
    • RELATIVE ENERGY?
    • NUMBERS?
    • SHAPES?
    • ORIENTATION?
    • NODE, NODAL PLANE
    • TYPES OF ORBITALS

ELECTRON CONFIGURATION

AUFBAU PRINCIPLE

PAULI EXCLUSION PRINCIPLE

HUND'S RULE --> GROUND-STATE

• H = 1s¹
• He = 1s²
• Li = 1s² 2s¹
• C = 1s² 2s² 2p_x¹ 2p_y¹ = 1s²2s²2p²
• Cl = 1s²2s²2p⁶3s²3p⁵

IONIC vs. COVALENT BONDS

IONIZATION ENERGY

ELECTRON AFFINITY

ELECTRONEGATIVITY

• IF THE DIFFERENCE IN ELECTRONEGATIVITY IS LARGE:
  • ELECTRONS ARE TRANSFERRED
  • GET AN IONIC BOND

• IF THE DIFFERENCE IN ELECTRONEGATIVITY IS SMALL:
  • ELECTRONS ARE SHARED
  • GET A COVALENT BOND

**LEWIS STRUCTURES!!**

CORRECT FORMULA

• WATER = H₂O
• CARBON DIOXIDE = CO₂
• CARBONATE ION = CO₃^-2

GROSS STRUCTURE

• BOND RULES
  • H = 1
  • Be = 2
  • B = 3
  • C = 4
  • N = 3
  • O = 2
  • F = 1

• FIND CENTRAL ATOM

• AVOID O-O (peroxide bond)
  • H₂O is H-O-H and not H-H-O
  • CO₂ is O-C-O and not C-O-O

• ADD BONDING AND NONBONDING OUTER ELECTRONS
  • H₂O = 8
  • CO₂ = 16
  • CO₃^-2 = 24

• OCTET RULE
  • SECOND ROW ELEMENTS!

• MULTIPLE BONDS

EXAMPLES:

WATER

AMMONIA

FLUORINE

NITROGEN

CARBON DIOXIDE

SULFUR DIOXIDE

CARBONATE ION

NITRATE ION

CARBONIC ACID, H₂CO₃

METHANOL, CH₄O

ACETIC ACID, CH₃CO₂H

EXCEPTIONS to the OCTET RULE

BORANE, BH₃

NITROGEN (IV) OXIDE, NO₂

SULFUR HEXAFLUORIDE, SF₆