CHEM1130 Inorganic Chem

• Theory


  Explanation of how something works
• Wave-particle duality


  The concept that particles can exhibit properties of both particles and waves
• Bohr worked with Rutherford
• Electrons


  Particles that are in constant motion and travel in orbits around the nucleus
• Energy levels


  Specific energy states that electrons can occupy around the nucleus
• Electron energy transitions


  1. Electrons absorb energy and move to a higher energy level

  2. Electrons release energy and return to a lower energy level
• Delta E


  The difference in energy between two energy levels, given by the formula Delta E = h*nu
• Electrons can only exist at discrete energy levels, not in between
• Bohr's theory works well for one-electron atoms but not for many-electron atoms due to the Heisenberg uncertainty principle
• Heisenberg uncertainty principle


  The position and momentum of a moving object cannot be defined at the same time
• Wave-particle duality


  Electrons can exhibit properties of both particles and waves
• Photoelectric effect


  • Electrons are emitted from a metal surface when light is shone on it
• The motion of particles can be described as three-dimensional standing waves originating at the nucleus
• Amplitude


  The maximum displacement of a wave from its resting position
• Node


  A point where the amplitude and intensity of a standing wave is zero
• Plum pudding model


  Atom looks like a plum pudding, with positive protons/positive region as the "cake" and electrons as the "fruits"
• Intensity


  The square of the amplitude of a wave
• The wave function describing the electron's motion has three variables: x, y, and z
• Subatomic particles


  • Electrons
  • Protons
  • Neutrons
• Rutherford planetary model


  Nucleus at the center of the atom, with protons and neutrons inside, and electrons orbiting the nucleus
• Electrons are negatively charged


  Protons are positively charged
• Development of atomic models

  Experiments (e.g. gold foil experiment) led to shift from plum pudding to planetary model
• Nuclear binding energy


  The amount of energy required to counteract the repulsion between protons in an atom
• Electrons are attracted to protons


  Protons are attracted to electrons
• Electrons are repelled by electrons


  Protons are repelled by protons
• Nucleus


  • Contains protons (positively charged) and neutrons (neutral)
• Table of constants


  • Provides values for mass of electron, proton, and neutron, as well as conversion factor between kilograms and atomic mass units
• Atomic number


  The number of protons in the nucleus of an atom
• Types of subatomic interactions

  • Gravitational interactions
  • Electrostatic interactions
  • Weak interactions
  • Strong interactions
• Mass number


  The total number of protons and neutrons in the nucleus of an atom
• Calculating atomic mass of hydrogen

  1. Sum mass of 1 proton and 1 electron

  2. Convert total mass from kilograms to atomic mass units
• Electrons


  • Negatively charged, housed in orbitals, constantly moving around the nucleus
• Atomic mass of hydrogen is less than sum of masses of proton and electron due to no nuclear binding energy required
• Gravitational interactions


  • Attractive force
  • Depend on mass and radius
  • Very weak
• Electrons do not go straight towards the protons due to the attraction, but move in a circular motion to prevent the atom from imploding
• Mass defect


  The difference between the mass of the nucleus and the sum of the masses of its protons and neutrons
• Electrostatic interactions


  • Occur between charged species
  • Can be attractive or repulsive
  • Depend on charge
• Calculating nuclear binding energy

  1. Convert atomic mass from atomic mass units to kilograms

  2. Calculate sum of masses of electrons, protons, and neutrons

  3. Subtract atomic mass from sum of masses to get mass defect

  4. Use Einstein's equation E=mc^2 to calculate nuclear binding energy from mass defect
• Relative mass of subatomic particles

  Proton = 1, Neutron = 1, Electron << 1 (e.g. 1/1835 or 1/1840)
• Nuclear binding energy can be used to calculate atomic mass, and vice versa