Summary: Orc1

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• 1 lecture 1 en 2

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• What is oganic chemistry?

  All organic compounds contain the element carbon
  -> carbon bonds to other carbons to create chains and rings (huge structures)
  -> not all carbon compounds are derived from living organisms

• What is an electon cloud?

  negatively charged electrons in a cloud around the nucleus 

• What are the three rules for the gound-state electron configuration?

  1. Lowest energy orbitals fill first: 1s -> 2s -> 2p -> 3s -> 3p -> 4s -> 3d 
  2. Electron spin can have only 2 orientations: up and down
   a maximum of two electrons can occupy an orbital, and they must be of opposite spin
  3. If two or more empty orbitals of equal energy are available electrons occupy each orbital with parallel spins until all orbitals have one electron 

• Why do atoms bond?

  because the compound that results is more stable and has lower energy than the separate atoms
  - Energy is released from the chemical system when a bond forms
  - Energy is consumed by the system when a bond breaks 

• What is a valence shell?

  outermost electron shell of an atom
  - Eight electrons in a valence shell (an electron octet) impart special stability to noble-gas elements (He, Ne, Ar, Kr, Xe, Rn)
  - Other elements have a tendency to take on electron configuration of the nearest noble gas 

• What can you tell me about ionic compounds?

  - Some elements achieve an octet configuration by gaining or losing electrons
  ->  The consequence is that you get a charge
  -> Donating = + charge, accepting = - charge
  - Ions form when an electron is gained or lost from a neutral atom
  - Ions are held together by electrostatic attraction forming an ionic bond

• What can you tell me about sp3 hybridization?

  Orbitals per atom:
  - 4 sp3 orbitals 
  - C atom forms 4 sigma bonds
  
  geometry:
  - tetrahedral 
  - bond angle 109.5º
  
  how to recognize in molecular structure:
  - only single bonds

• What can you tell me about sp2 hybridization?

  Orbitals per atom:
  - 3 sp2 orbitals and 1 p obital
  - C atom forms 3 sigma bonds and 1 π bond
  
  geometry:
  - planar
  - bond angle 120º
  
  how to recognize in molecular structure:
  - 1 double bond

• What can you tell me about sp hybridization?

  Orbitals per atom:
  - 2 sp orbitals and 2p orbitals
  - C atom forms 2 sigma bonds and 2π bonds
  
  geometry:
  - linear
  - bond angle 180º
  
  how to recognize in molecular structure:
  - 1 triple or 2 double bonds

• What is a dipole moment (µ)?

  A measuer of the net polarity of a molecule
  -> polar substances (µ≠0) are more soluble in polar solvents like water (hydrophilic) orr methanol