Electron arrangements

Energy levels
1. Electrons in different shells have differing amounts of energy
2. Shells are called main energy levels
  1. Divided into sub-levels
3. S sublevel
  1. Can hold 2 electrons
  2. Spherical
4. P sublevels
  1. Can hold 6 electrons
  2. 3 dumbell shape
5. D sublevel
  1. Can hold 10 electrons
  2. 5 dumbell shape
6. F sublevel
Quantum mechanics
1. Developed 1920's
2. Schrodinger equation
3. Give the probability of finding an electron in a given volume of space called an atomic orbital
Atomic orbitals
1. Electron
  1. Cloud of negative charge
  2. Fills volume known as its atomic orbital
2. Concept
  1. Different orbitals = different energies
    1. Number tells us which energy level it corresponds to
  2. Atomic orbitals of each main level have different shapes which have slightly different energies
  3. Shapes of orbitals represent a volume of space in which there is a 95% probability of finding an electron
  4. First main energy level consists of just one s orbital, the second has an s and a p,
  5. Any atomic orbital can hold 2 electrons
    1. S orbitals can hold up to two electrons
    2. P orbitals can hold 2 each, but come in groups of 3
    3. D orbitals can hold 2 each, but come in groups of 5
Spin
1. Electrons have a property called spin
2. 2 electrons in the same orbital must have opposite spin
  1. This creates a magnetic attraction between the two, allowing them to sit in the orbital without repulsion
3. Electrons are usually represented by arrows pointing up or down to show different directions of spin
4. Repulsion
  1. Has to be some sort of attraction to hold e- in an orbital
Order of filling
1. Aufbau principle
  1. Lower energy orbitals filled first
  2. No atomic orbital can hold more than 2 electrons
  3. 4s fills before 3d
2. Hunts rule
  1. FIll singly before pairing
  2. Opposite number of spins minimised

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Electron arrangements

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	Created by Beth Ritchie over 10 years ago