ATOMIC NUMBER AND MASS NUMBER

• Protons and Neutrons - carry the bulk of the mass of an atom

  Electrons - occupy the space around the nucleus providing volume to the atom
• Atomic Models

  1. Solid Sphere Model
  2. Plum Pudding Model
  3. Nuclear Model
  4. Planetary Model - Neils Bohr - electrons move in orbits around nucleus
  5. Electron Cloud Model - Erwin Schrondinger - electrons move in waves
• Zero Charge

  • atoms in neutral state
  • same number of protons and electrons cancels out the charges
• Berzelius Notation of an Element

  A) Atomic Number (Z)

  B) Atomic Mass (amu) (a)

  
• Atomic Mass unit (amu) -average atomic mass

  atomic and mass number - whole number
• Atomic Number (Z)

  • proton number (p)
  • proton = electrons if neutral atom
  • does not change during chemical reactions
• Mass Number (A)

  • atomic mass
  • electron's mass is negligible

  A = p + n

  A = Z + n

  n = A - Z
• Charge Number (q)

  • q = p - e (depends which particles is greater in quantity you'll change sign)

  Ex:

  A is 55; Z is 25; and q is +5

  e = p - q

  e = 25 - 5

  e = 20
• The Atomic Model

  A) Solid Sphere Model

  B) Plum pudding

  C) Nuclear

  D) Planetary

  E) Quantum

  F) John Dalton

  G) JJ Thomson

  H) Ernest Rutherford

  I) Niels Bohr

  J) Erwin Schrodinger