Lecture 01, 2

• What is the focus of organic chemistry?

  Drawing organic structures correctly
• What does the structure of atomic orbitals describe?

  The shape and orientation of electron clouds
• How do you determine the electronic configuration of an atom?

  By using the principal quantum number
• What is a bond dipole moment?

  A measure of charge separation in a bond
• What do Lewis structures represent?

  The bonding and lone pairs in molecules
• What is the skeletal formula used for?

  • Represents organic molecules
  • Simplifies complex structures
  • Omits hydrogen atoms
• What does the principal quantum number (N) indicate?

  The energy level of an electron
• What does the equation $E =$$1/n^2$ represent?


  The energy levels of electrons in atoms
• What happens when an electron moves between energy levels?

  Precise amounts of energy are released
• What defines an atomic orbital?

  A region of space for electron probability
• What does the wave function Ψ describe?

  The size, shape, and orientation of orbitals
• What is a node in wave functions?

  A point where amplitude is zero
• What are the key principles of electronic configurations?

  • Aufbau principle: fill lowest energy orbitals first
  • Hund's rule: electrons occupy different orbitals before pairing
• How do atoms stay together in ionic bonding?

  Through electrostatic attraction
• What characterises covalent bonding?

  Electrons are shared between atoms
• What is the purpose of ionic bonding?

  To achieve a noble gas configuration
• What is a non-polar covalent bond?

  Electrons are shared evenly between atoms
• What happens in a polar covalent bond?

  Electrons are shared unevenly between atoms
• What do Lewis structures show?

  The bonding and lone pairs in a molecule
• What is the formula for calculating formal charge?

  Formal charge = valence electrons - (lone pairs + bonds)
• What causes a dipole moment?

  Separation of charge due to electronegativity differences
• How is the dipole moment calculated?

  Charge separation times bond length
• What does an electrostatic potential map show?

  Regions of partial positive and negative charge
• What electronegativity difference indicates a non-polar bond?

  Less than 0.4
• What does an electronegativity difference of 2 or more indicate?

  It indicates ionic bonds
• What determines the overall polarity of a molecule?

  • Shape of the molecule
  • Polarity of its bonds
  • Presence of lone pairs
• Why do carbon dioxide and tetrachloromethane have no net polarity?

  Symmetrical shapes cancel individual bond polarities
• What are atomic orbitals in terms of wave functions?

  They can be combined like waves
• What is hybridisation in atomic orbitals?

  Combination of orbitals on the same atom
• What happens when waves are in phase?

  They add together and increase amplitude
• What occurs when waves are out of phase?

  They cancel out, creating a node
• What is the result of overlapping 1s orbitals?

  Formation of a bonding molecular orbital
• Where does electron density lie in sigma bonding?

  Between the nuclei of bonded atoms
• What happens during the formation of a σ* antibonding MO?

  1s orbitals overlap out of phase

  
• What occurs when two p orbitals overlap along the line between nuclei?

  They create bonding and antibonding orbitals

  
• What is the result of destructive overlap of p orbitals?

  An antibonding orbital with a node

  
• What is the result of s and p orbital overlap?

  Formation of bonding and antibonding MOs

  
• What leads to the formation of a π-bonding MO?

  Sideways overlap of two p-orbitals

  
• What does a double bond consist of?

  A sigma bond and a pi bond
• What does a triple bond consist of?

  A sigma bond and two pi bonds