bonding & matter

• how are elements in periodic table arranged?

  increasing atomic no.
• what is similar about groups?


  same no. of electrons on outer shell
• give a trend for metals


  more reactive further down a group
• define catalyst


  something that can speed up a reaction without being used up
• what is the product of an alkali metal + water?

  metal hydroxide + hydrogen gas
• what is the product of an alkali and oxygen?

  metal oxide
• product of lithium + oxygen?

  lithium oxide Li2O
• product of sodium + oxygen?


  sodium oxide Na2O

  sodium peroxide Na2O2
• product of potassium + oxygen?


  potassium peroxide K2O2

  potassium superoxide KO2
• explain displacement reactions

  more reactive halogens always displace less reactive halogens

  Cl2 (g) + 2KBr (aq) -> Br2 (g) + 2KCl (aq)

  bromine is replaced by chlorine
• what are the ways of showing covalent bonds?

  dot and cross diagrams

  displayed formula
• what are the types of substances covalent bonds can form?

  simple molecular substances

  giant covalent structures

  polymers
• give examples of simple molecular substances

  CH4

  CO2

  H2O
• how can polymers be drawn?

  monomer in curved brackets, bond lines must go outside brackets also
• define ion


  charged particle
• what groups usually form ions?


  1, 2 , 3, 7
• what is ionic bonding?

  transfer of electrons when a metal and non-metal react together (opposite charges) and works via electrostatic forces of attraction
• dot and cross diagrams in brackets are used for ionic compounds
• what are the properties of ionic compounds?

  high melting/boiling points

  many strong ionic bonds

  when aqueous/molten - ions can move and therefore can conduct electricity
• chemical symbol for nitrate


  NO3-
• chemical symbol for carbonate


  CO3 2-
• chemical symbol for ammonium


  NH4+
• what is covalent bonding?


  electrons are shared between two non-metals
• what are the types of covalent structures?

  simple mollecular structures

  giant covalent structure
• what are the properties of simple molecular structures?

  weak intermolecular forces

  strong covalent bonds
• give examples of simple molecular structures?

  H2O, Cl-Cl, CH4
• what are the properties of giant covalent structures?

  regular repeating lattices

  high melting/boiling points

  do not conduct electricity (except graphite)
• what are the allotropes of carbon?

  diamond

  graphite

  graphene

  nanotubes

  buckminster fullerenes
• what are the chemical and physical properties of diamond?

  has a giant covalent structures

  covalent bonds between 2 carbon atoms (very strong)

  has high melting/boiling point

  shiny

  very hard
• what are the chemical and physical properties of graphene?

  3 strong covalent bonds per atom

  1 layer thick

  a hexagonal sheet

  makes nanotubes/buckminster fullerenes

  can conduct as it has a delocalised electron
• what can graphene be used for in day-to-day life?

  electronics

  medicine

  as industrial catalysts
• what are the physical and chemical properties of graphite?

  has flat sheets that can slide (layer of graphene)

  weak intermolecular forces of attraction

  high melting/boiling points

  conducts electricity as it has a delocalised electron
• what is a buckminster fullerenes?C60

  interlocking hexagons and pentagons

  3 strong covalent bonds per atom

  drug delivery - medicine - batteries
• what is metallic bonding?

  metal + metal

  • electrostatic forces of attraction
  • sea of delocalised electrons therefore are conducts
  • have high melting/boiling points
  • are malleable - have layers that can slide over one another
• what are alloys?

  2 or more diff elements usually of diff sizes
• why are alloys stronger than pure metals?


  disrupts the regular structure -> layers can't slide therefore are harder than pure metals
• what are polymers?


  large molecules made up of many monomers
• what types of bonds are there in polymers?


  covalent
• what are the polymers' melting/boiling points like?


  higher than simple molecular structures

  lower than giant covalent structureds
• how are ionic equations written?


  • if the ion is due to lost electrons -> leftif the ion is due to gained electrons -> righte.g :
  • Na -> (Na+) + e-
  • Cl + (e-) -> Cl-
  • Mg -> (Mg2+) + 2e-
  • O + (2e-) -> O2-