fundamentals

• What is the electronegativity of carbon on the Pauling scale?

  2.55
• Why is a carbon-carbon single bond not polarised?

  Both carbon atoms have the same electronegativity
• What happens when bonds are formed between different elements?

  The more electronegative element gains a partial negative charge
• What is the electronegativity of fluorine on the Pauling scale?

  3.98
• How can we illustrate the polarisation of bonds?

  Using the Greek letter delta
• Why is it essential to know the electronegativity of elements in organic molecules?

  It helps understand why organic reactions occur
• What does tetravalent mean in relation to carbon?

  Carbon forms four bonds
• What happens when carbon has four bonds?

  It forms stable, neutral species
• Can carbon have five bonds?

  No, carbon never has five bonds
• What is a carbocation?

  A positively charged carbon species
• What is a carbanion?

  A negatively charged carbon species
• Why is it important to draw bond angles and lengths accurately in organic molecules?

  It affects the reactivity of the molecule
• What is the bond angle for carbon-carbon single bonds?

  Approximately 109°
• What is the bond angle for carbon-carbon double bonds?

  Approximately 120°
• What is the bond angle for carbon-carbon triple bonds?

  Linear, 180°
• What is the significance of steric hindrance in organic molecules?

  It affects the reactivity of the molecule
• Why can rotation occur around carbon-carbon single bonds?

  Efficient orbital overlap is maintained
• Why can't rotation occur around carbon-carbon double bonds?

  Efficient overlap of p-orbitals is not possible
• What is the length of a C-C single bond?

  1.57Å
• What is the length of a C-C double bond?

  1.35Å
• What is the length of a C-C triple bond?

  1.21Å
• What does Heisenberg’s Uncertainty Principle state about electrons?

  We cannot know their precise location
• What are atomic orbitals?

  Shapes that describe probable electron locations
• Which orbitals are most concerned in this topic?

  s and p orbitals
• How many electrons can each orbital house?

  Two electrons
• What is the Pauli exclusion principle?

  Two electrons with the same spin cannot occupy the same orbital
• What is Hund’s rule?

  Electrons are only paired if necessary
• What is hybridisation?

  Combining atomic orbitals to form new orbitals
• What is the hybridisation state of carbon in methane?

  sp3 hybridisation
• What is the shape of methane due to hybridisation?

  Tetrahedral shape

  
• What is the bond strength of a C-H bond in methane?

  420 kJ/mol
• What is the bond strength of a C-C bond in ethane?

  377 kJ/mol
• What is the hybridisation state of carbon in ethylene?

  sp2 hybridisation
• What is the bond angle in sp2 hybridised orbitals?

  120°
• What is the bond strength of a C-C π bond?

  260 kJ/mol
• What is the bond strength of a C-C σ bond?

  350 kJ/mol
• What is the hybridisation state of carbon in acetylene?


  sp hybridisation
• What is the bond strength of a C-C bond in acetylene?

  954 kJ/mol
• What is the bond strength of a C-H bond in acetylene?

  549 kJ/mol
• What is the bond angle in ammonia?

  107.3°