Structure 1.1-1.3

• Aufbau principle


  subshells and orbitals are filled from lowest energy to highest energy
• Pauli Exclusion Principle


  an orbital may hold a maximum of two electrons. Both electrons must have a different spin
• Hund's rule 


  every orbital in a subshell must be filled with one electron with parallel spin first before an orbital is filled with a second electron
• Filtration

  • insoluble solid from a liquid
  • difference in physical property: particle size
• Evaporation

  • soluble solid from a liquid
  • difference in physical property: boiling point
• Distillation

  • homogenous/miscible liquids
  • boiling point/temperature
• Paper chromotography

  • soluble substance in solvent
  • difference in physical property: solubility in the mobile phase and attraction in the stationary phase
• Recrystallisation

  • purifying a compound
  • difference in physical property: difference in solubility/a solvent that dissolves more readily at high temperature
• Pure substance


  has fixed properties and uniform chemical composition. Can not be physically separated into smaller substances
• Mixture


  combination of two or more different compounds/elements that are not chemically combined. Can be physically separated into smaller substances
• Element


  composed of one type of element and can not be broken down into smaller substances
• Compound

  composed of two or more different elements chemically bonded in a fixed ration
• Heterogeneous


  has a non-uniform composition and varying properties
• Homogenous


  has a uniform composition and properties
• Miscible 


  liquids that mix to form one uniform layer of homogeneous mixture
• Immiscible 


  liquids that do not mix but form two separate layers (heterogeneous)
• Endothermic process


  substance changes from more condensed state to a less condensed state (energy is absorbed by the surrounding particles)
• Temperature


  the measure of the average kinetic energy pf the particles in a substance
• Mass spectrometry


  Provides info about:

  • number of isotopes in a given sample of an element
  • relative isotopic mass of each isotope
  • relative abundance of each isotope
• relative isotopic mass


  the mass of an isotope relative to 1/12 of a carbon-12 atom
• relative atomic mass


  the weighted average of the isotopic masses, according to their relative abundances, relative to 1/12 the mass of a carbon-12 atom
• the larger the isotopic mass, the lower the percentage abundancy
• Light


  electromagnetic wave
• higher frequency= higher energy
• longer wavelength= lower energy
• violet= shortest wavelength= highest energy
• red=longest wavelength=lowest energy
• infrared is BELOW visible light (lower energy), ultra violet is ABOVE visible light (higher enegy)
• ground state


  the lowest energy state, closest to the nucleus
• excited state


  when the energy of an electron makes it jump to a higher energy level
• absorbed


  when the electron moves to a higher energy shell and absorbs energy
• emitted


  when the electron moves to a lower energy level and emits energy as a photo of light
• for an electron to become excited:

  the energy absorbed must be the exact energy difference between the two energy levels the electron is moving between
• convergence


  at higher energies, the energy levels are moving further away from the nucleus. As the distance from the nucleus increases, the wavelengths get shorter and the difference in energy between successive energy levels decreases, causing them to get closer together
• ionization energy


  • the limit energy
  • the minimum energy required to remove one electron from one gaseous hydrogen atom
  • the highest possible energy level for an atom
• CHROMIUM (Cr) AND COPPER (Cu) = exceptions to the normal electron shell configuration pattern
• at excited states, one or more electrons are found in a higher energy subshell
• isoelectronic


  same number of electrons (eg. S2- and Cl-)
• lighter particles (smaller isotopes)= deflect more in a mass spectrometer
• higher charge= deflect more in a mass spectrometer