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• three states of matter

  • solid
  • liquid
  • gas
• describe the arrangement and movement of particles in solids

  • the particles are packed closely together in a regular arrangement
  • the particles vibrate in fixed positions
• describe the arrangement and movement of particles in liquids

  • the particles are close together but are able to move past each other
  • the particles vibrate and move around each other
• describe the arrangement and movement of particles in gases

  • the particles are well separated with no arrangement
  • the particles vibrate and move freely at high speeds
• how do the relative energies of particles in a solid, liquid and gas compare?

  • particles in a solid have the lowest energy
  • particles in a gas have the highest energy
• state changes

  A) solids

  B) liquids

  C) gases

  D) melting

  E) freezing

  F) condensing

  G) boiling

  H) subliming

  
• describe the forces between particles in solids, liquids and gases

  • solids - strong forces of attraction between particles which keep them in fixed positions
  • liquids - weaker attractive forces than in solids
  • gases - weakest intermolecular forces so particles move randomly
• how does a physical change differ from a chemical change?

  • a physical change involves changes in the forces between particles. the particles themselves remain the same and the chemical properties remain the same.
  • a chemical change is different as it affects the chemical properties of the substance
• true or false?

  ‘physical changes are relatively easy to reverse’

  TRUE

  relatively easy to reverse since no new product is formed during the changes of state
• describe what happens, in terms of particles, when a solid is heated and melts into a liquid

  • when heated, particles absorb thermal energy and convert it into kinetic energy
  • the particles in the solid vibrate more, causing the solid to expand until the structure breaks and the solid turns into a liquid
• describe what happens, in terms of particles, when a liquid is heated and evaporates into a gas

  • when heated, the particles in a liquid expand
  • some particles on the surface gain sufficient energy to overcome the intermolecular forces and evaporate
  • at the boiling point, all of the liquid particles gain enough energy to evaporate
• substance 'a' melts at -200 degrees celsius and boils at -183 degrees celsius

  what state is it at -174 degrees celcius?

  gas
• substance 'b' melts at -5 degrees celsius and boils at 23 degrees celsius

  what state is it at -7 degrees celcius?


  solid
• why do solids, liquids and gases expand when heated?

  • when a substance is heated, the molecules vibrate faster
  • this causes the space between the atoms to increase
• what is an advantage to the current particle model?

  it provides a simple understandable model to explain the three states of matter
• what are particles in the particle model represented by?

  inelastic spheres
• what are the limitations of the particle model?

  • doesn’t take into account forces of attraction between particles. the amount of energy required to cause a change of state depends on these forces
  • doesn’t take into account the size of particles and space between them. the nature of particles depends on the structure and bonding of a substance
• liquid 'a' has a higher boiling point that liquid 'b'

  what does this tell you about the forces between particles in liquid 'a'?

  it has greater forces of attraction between the particles than liquid 'b'
• elements

  substances made up of only one type of atom
• compounds

  made up of atoms of different elements
• what are the three subatmoic particles in an atom?

  • electron
  • proton
  • neutron
• who described atoms as solid spheres?

  john dalton
• what was dalton's theory?

  • atoms cannot be created, divided or destroyed
  • atoms of the same element are exactly the same and atoms of different elements are different
  • atoms join with other atoms to make new substances
• what discovery caused the dalton model of an atom to change?

  the discovery of subatomic particles
• how did jj thompson discover the electron?

  • thomson conducted an experiment using a cathode ray tube
  • the beam moved towards the positively charged plate so he knew the particles must have a negative charge
• describe the plum pudding model by jj thompson

  A) cloud

  B) positive

  C) electron

  
• who designed and carried out the gold foil experiment?

  • Ernest Rutherford designed the experiment
  • Geiger and Marsden carried out the experiment
• what did Rutherford discover from his gold foil experiment? he shot a beam of positively charged particles into a sheet of gold foil

  • most particles passed straight through indicating that atoms were mostly empty space
  • a few particles were deflected and a few bounced directly back showing that there must be a positively charged nucleus
• describe Rutherford's model of the atom

  A) orbit

  B) electrons

  C) nucleus

  
• what change did Niels Bohr propose to the nuclear model of an atom?

  electron shells around the nucleus
• structure of an atom

  A) electron

  B) neutron

  C) proton

  D) electron shell

  
• where is the mass of the atom concentrated?

  nucleus
• compare the sizes of the nuclear radius and the atomic radius

  the nuclear radius is much smaller than the atomic radius
• compare the typical size of atoms and small molecules

  • atoms and small molecules are both incredibly small
  • small molecules are larger than atoms because they are made of atoms
  • the typical atomic radii and bond length are in the order of 10^-10m.
• what are the relative masses of a proton, neutron and electron?

  • proton: 1
  • neutron: 1
  • electron: 1/1836
• what are the relative charges of a proton, neutron and electron?

  • proton: +1
  • neutron: 0
  • electron: -1
• ion


  an atom or molecule with a positive or negative charge
• how is an ion formed?

  • when an atom or molecule gains or loses electron(s)
  • positive ions (cations) are formed when an electron is lost
  • negative ions (anions) are formed when an electron is gained
• what does the atomic number tell you about an element?

  it is unique to each element and tells you the number of protons an element has
• what does the mass number tell you about an element?

  the combined total of the number of protons and neutrons in the nucleus of an atom of an element