C1 - Particles

• particle

  a very small piece of something
• solid


  The particles are tightly packed and don't move around
• liquid

  particles are close together with no regular arrangement and will vibrate, move about, and slide past each other
• gas


  Particles are well separated with no regular arrangement. Particles gas vibrate and move freely at high speeds.
• melting

  solid to liquid
• Evaporation

  Liquid to gas
• condensation


  Gas to liquid
• solidifying

  liquid to solid
• sublimation

  solid to gas
• physical change

  reversible change that does not lead to the formation of a new substance
• physical change examples


  ice melting, mixing sand with water
• chemical change

  irreversible change that leads to the formation of a new substance
• chemical change examples

  burning, rusting
• chemical change in term of particles

  particles break up and then join together
• physical change in term of particles

  particles stay the same but the arrangement and movement changes
• how do changes of state occur?

  Energy must be transferred, by heating, to a substance for these changes of state to happen. During these changes the particles gain energy.
• which state of matter has the most energy and why?

  gases- move around quickly in all directions
• which state of matter has the least energy and why?

  solids- vibrate around a spot
• Limitations of the particle model

  - the forces between particles

  - the size of the particles

  - the space between particles

  - particles are 3D not 2D
• why do we use standard form notation

  to represent very big or very small numbers more easily
• 1 picometre

  10^-12 meters
• 1 nanometre

  10^-9 meters
• 1 micrometre

  10^-6 meters
• 1 milliliter

  10^-3m
• ratio

  used to compare 2 different numerical valves in terms of their relative sizes
• protons

  Positively charged particles
• neutrons


  neutral charge
• electrons


  Negatively charged particles
• the vast majority of an atoms mass comes from the

  nucleus
• the periodic table is arranged in order of

  atomic number
• number of electrons=

  number of protons
• number of neutrons=


  atomic mass - atomic number
• atomic number

  number of protons
• what determines the element of the atom

  number of protons in the nucleus
• Isotopes


  Atoms with the same number of protons but different numbers of neutrons
• isotopic notation

  A symbol that identifies the isotope of an element
• ions

  formed when atoms gain or lose electrons
• cation

  if a electron was lost, a positive ion
• anion

  if a electron was gained, negative ion
• John Dalton (1803)

  all atoms of an element are identical, all matter is made of atoms