Year 11 Chemistry

• Homogenous Mixture


  Uniform distribution e.g. salt and water, wine
• Heterogeneous Mixture


  Non-uniform distribution e.g. sand and water
• METALS 

  → high conductivity of electricity and heat 

  → malleable 

  → lustrous 

  → ductile 

  → solid at room temperature 

  → high melting and boiling point 
• METALLOIDS 

  → low electrical conductivity 

  → high melting and boiling points

  → all solids 

  → low lustre 
• NON-METALS 

  → poor conductors of heat and electricity 

  → dull 

  → brittle 

  → can be solids, liquids or gases 
• Isotopes: a form of a chemical element when the atomic number of an element is the same while the amount of neutrons is different. 
• Nuclear Radiation: Nucleus of the atom emitting radiation to become stable. 
• Alpha 

  • Emits positive charged 
  • Weak penetrating power 
  • Helium 
• Beta 

  • Negatively charged particle 
  • Medium penetrating power 
• Gamma 

  • Neutral charge 
  • High penetrating power 
• Flame Tests: Used to identify if there is a metal in a sample. 
• Each metal has a unique flame colour due to the different electron configurations and energy levels hence different wavelengths that produce different colours. 
• Emission Spectra:

  • When electrons are heated they become excited, they emit electromagnetic radiation or light 
  • The emission spectra displays patterns of light 
  • Left as a high energy and right has low energy 
  • Each line in the emission corresponds to a specific electron transition/jump. 
• Absorption Spectra: when atoms absorb wavelengths/light, therefore there is no coloured lines and instead black lines 
• Bohr 

  • Electrons orbit nucleus in a fix circular orbit
  • Electrons cannot exist between 2 energy levels 
• Schrodinger 

  • Electrons behave as waves around nucleus 
  • Orbit in a 3D space in orbitals 
  • Shells contain subshells such as S P D F 
• Aufbau Principle: 

  The orbitals with the lower energy levels must be filled first 
• Pauli Exclusion Principle:

  Each orbital must have a maximum of  2 electrons with different spins. 
• Hund’s Rule: 

  each each subshell must first be filled with one electron with the same spin 
• ionisation energy and electronegativity  increases across a group 

  Ionisation energy and electronegativity decreases down a group
• Intramolecular (within a molecule):
• Intermolecular (between molecules)