Molecular Structure

Question 1

Bond Dissociation Energy

Answer 1

• The energy released when a bond is formed is the amount of energy needed to be absorbed by the olecule to break the bond
• Large bond dissociation energy is associated with a strong bond

Question 2

Inductive Effect

Answer 2

• An electronegative atom withdraws electron density and thus can:
  
  • Increase acidity, electrophilicity
  • Decrease basicity, nucleophilicity
  • F, O, N, Cl, Br, I, S, C, H
• Alkyl groups are electron donating

Question 3

Aromaticity

Answer 3

• Aromaticity is stability generated from having 4n + 2 pi electrons in a continuous overlapping ring of p-orbitals, where n is any integer including 0
• Also known as Hückel rule

Question 4

Brønsted-Lowry

Lewis

Answer 4

• Brønsted-Lowry deals with the movement of protons
  
  • Acids are proton donors
  • Bases are proton acceptors
• Lewis deals with the movement of electrons
  
  • Acids are electron acceptors
  • Bases are electron donors

Question 5

Electrophiles and Nucleophiles

Answer 5

• Electrophiles seek electrons, and are lewis acids
  
  • Accepts and electron
• Nucleophiles seek nucleuses, and are lewis bases
  
  • Donates an electron

Question 6

Acid and Base Strength Factors

Relationship Between Acid/Base and Respective Conjugate

Answer 6

• Acidity depends on intramolecular forces on the bond to the acidic proton
  
  • Inverse relationship b/w bond strength to proton and acidity of proton
• Basicity can be easily thought of as the opposite of acidity
  
  • Electron-donating groups will increase basicity
• The strength of an acid or a base can be determined from the stability of its conjugate: the more stable the conjugate, the weaker the conjugate and the stronger the respective compound
  
  • If the conjuage is very stable, then the respective compound must have been very reactive