GEN CHEM

• Planetary Model


  July 1913

  Danish physicist Niels Bohr published the first of a series of three papers introducing his model of atom.
• Quantum Mechanical Model / Electron Cloud Model


  1926

  New model emphasized that we cannot determine the exact position of the electron at a specific time
• Quantum Numbers


  set of numbers used to describe the position and energy of an electron in an atom
• Energy Levels / Shells


  before the electron cloud model

  Niels Bohr speculated that electrons orbit at a fixed distance around the nucleus and has a definite energy
• Four physicist in 1920s

  1. Werne Heisenberg
  2. Louis de Broglie
  3. Erwin Schrondinger
  4. Alber Einstein
• Other physicist:

  1. Max Planck
  2. Paul Dirac
  3. Wolfgang Pauli
  4. Richard Feynman
• Heisenberg Uncertainty Principle


  we must abandon the notion of an electron as a particle moving around the nucleus in a defined path

  it is impossible to know precisely where an electron is and what path it follows
• Principle Quantum number 


  also called main energy shell, shell, 1st quantum number

  denoted by n
• Angular Momentum Quantum Number


  subshell or sub energy level

  denoted by cursive l

  describe the general shape an electron occupies
• Orientation:

  s - 1

  p - 3

  d - 5

  f - 7
• names

  S (sphere)

  P (primary)

  D (diffuse)

  F (fundamental)
• Sub-energy level / orbital

  s - 0

  p - 1

  d - 2

  f - 3
• Magnetic Quantum Number


  denoted by ml

  describes the orbital orientation in space
• Spin Quantum Number


  denoted by ms

  describe the spin for a given electron

  two associated spin: +1/2 and -1/2

  single orbital can hold a max of 2 electron
• Hund's Rule


  all electrons occupy empty orbitals first; all must spin upward
• Atom gains electron = radius increases
• Pauli's Exclusion Principle


  states that no two electron in an atom can have the same set of quantum numbers
• Johann Dobereiner


  first chemist to recognize patterns in element with the law of triads
• Ionization Energy


  the energy needed/ required to remove an electron
• Weights

  Alexander Beguyer de Chanqourtios - scientist who arranged all the known element in his time in periodic elements
• John Newlands


  scientist who suggested that elements should be arranges in octaves
• 7


  maximum number of n in modern periodic time
• 19


  sushells containing electrons
• 42


  total electrons can all "p" subshell house
• Noble Gases

  2 He

  10 Ne

  18 Ar

  36 Kr

  54 Xe

  86 Rn

  118 Og
• 118


  maximum electron can exist in an atom
• Electron Affinity


  trend that refers to the electron-wanting of an atom
• Electron Configuration


  distribution of electrons

  a way to locate elements

  "configure" means arrangement of electrons
• how much it accomodates:

  s = 2

  p = 6

  d = 10

  f = 14
• Aufbau Principle


  german word "Aufbean" to build

  originates from Pauli's exclusion
• Unusual Electron Configuration

  Cu (copper)

  Ag (silver)

  Au (gold)

  Pd (palladium)

  Cr (chromium)

  Mo (molybdenum)