Bonding & Structure & Properties of Matter

• for a substance to change from one state to another what must happen


  energy must be transferred

  • particles gain energy
  • this breaks some of the attractive forces between particles during melting
• what is needed for both evaporation and boiling of a liquid

  more energy is needed to overcome the remaining chemical bonds between the particles
• what is the difference between evaporation and boiling

  • for evaporation -> particles leave the surface of the liquid only
  • for boiling -> gas bubbles form throughout the liquid before rising to the surface and escaping
• what is the amount of energy needed for a substance to change state dependant on


  the strength of the attractive forces between particles

  • the stronger the forces of attraction the more energy needed to break them apart
  • substances with stronger attractive forces generally have higher melting + boiling points
• what are the properties of solids

  • arranged in a regular pattern
  • vibrate in a fixed position
  • tightly packed together
  • low amounts of kinetic energy
  • unable to flow + be compressed
• what are the properties of liquids

  • randomly arranged
  • particles can move around each other
  • more kinetic energy than solids
  • can flow
  • cannot be compressed
• what are the properties of gases

  • randomly arranged
  • move around very quickly in all directions
  • highest amounts of kinetic energy
  • can flow + be compressed
• what are the limitations of the particle model

  • chemical bonds between particles arent shown
  • particles are inaccurately shown as solid sphere
• what are the four state symbols

  • s -> solids
  • l -> liquids
  • g -> gas
  • aq -> aqueous
• what are aqueous solutions

  formed when a substance is dissolved in water
• if a temperature of a substance is lower than the melting point, what is its state


  solid
• if a temperature of a substance is in between the melting point + boiling point, what is its state


  liquid
• if a temperature of a substance is higher than the boiling point, what is its state

  gas
• when does an element become an ion

  when the element loses or gains electrons
• metals lose electrons to become what


  positively charged
• non metals gain electrons to become what

  negatively charged
• do group 1 + group 2 elements lose or gain electrons

  lose electrons
• do group 6 + group 7 elements lose or gain electrons

  gain electrons
• what are the three types of bonding

  • ionic bonding
  • covalent bonding
  • metallic bonding
• what does metallic bonding occur between

  metals only
• describe what metallic bonding involves

  • metals form giant structures where outer shell electrons are free to move
  • the metallic bond is the force of attraction between these delocalised electrons + positive metal ions
  • this bond is strong so metals maintain regular structure + high melting points+ high boiling points
• what does ionic bonding occur between

  a metal + non metal
• describe what ionic bonding involves

  • metals react with non metals by transferring electrons
  • this forms negative and positive ions
  • the opposite charges are strongly attracted by electrostatic forces -> an ionic bond
• what do ionic compounds form

  giant lattices

  • there are strong electrostatic forces of attraction acting between oppositely charged ions to make up the giant ionic lattice
• what are the properties of ionic compounds

  • high melting + boiling points -> lots of energy is needed to overcome electrostatic forces of attraction
  • cannot conduct electricity in a solid -> ions are not free to move
  • can conduct electricity in molten or solution form -> as ions are free to move + carry electrical current
• what does covalent bonding occur between

  non metals only
• describe what covalent bonding involves

  the sharing of a pair of electrons between atoms to gain a full outer shell

  • shown through dot and cross diagrams overlapping shells
• what are the properties of simple covalent structures

  • low melting + boiling points -> weak intermolecular forces holding molecules together break when substances are heated
  • cannot conduct electricity -> they dont have any free delocalised electrons
• what are the properties + structure of diamond

  • each carbon atom is bonded to 4 other carbon atoms -> it is very strong
  • high melting + boiling points -> lots of energy needed to break strong covalent bonds between each carbon atom
  • doesn't conduct electricity -> no free or delocalised electrons
  • similar structure to silicon dioxide -> strong covalent bonds + high melting and boiling point
• what are the properties + structure of graphite

  • carbon layer arranged in hexagons -> each carbon is bonded to 3 other carbons + 1 free delocalised electrons
  • layers held together by weak intermolecular forces -> layers of carbon can slide over each due to lack of strong bonds
  • can conduct electricity -> has delocalised electrons to carry charge
  • high melting point -> lots of energy needed to break covalent bonds between each carbon atom
• what are the properties + structure of graphene

  • a single layer of graphite structure
  • very strong -> as with graphite each carbon bonds to 3 other carbons + 1 delocalised electron making it very strong
  • can conduct electricity -> has delocalised electrons to carry charge
  • can be added to other materials to make them even stronger
• what does nanoscience relate to

  • structures that are 1-100nm in size
  • they have high SA:V ratios -> a smaller amount is needed compared to normal sized particles
• what is the diameter of a coarse particle

  2500nm - 10000nm
• what is the diameter of a fine particle

  100nm - 2500nm
• what are polymers

  • long chain molecules made up of many smaller units of monomers
  • has intermolecular forces between polymer molecules
  • these forces attract polymer chains to one another
  • the longer the chain -> the stronger forces of attraction -> making stronger materials
• what are fullerenes

  • molecules of carbon shaped like hollow tubes or balls
  • they are arranged in hexagons of 5 or 7 atoms
• what was the first fullerene to be discovered

  • buckminsterfullerene
  • C60 -> it has 60 carbon atoms in it
• what are fullerenes used for

  to deliver drugs into the body
• what are nanotubes

  • tiny carbon cylinders that are longer than wider
• what are the properties of nanotubes

  • they can conduct electricity
  • they strengthen materials without adding much weight
  • these properties make them useful in electronics + nanotechnology