C2 Bonding, Structure and Properties of Matter

• What are the three states of matter?

  Solid, liquid and gas.
• How are the states of matter described?

  With the 'particle model'.

  Particles are represented by small solid spheres.

  It can be used to explain how the particles are arranged and how they move.
• Solids?

  Have a regular arrangement.

  Are very close together.

  Vibrate about fixed positions.
• Liquids?

  Have a random arrangement.

  Are close together.

  Flow around each other.
• Gases?

  Have a random arrangement.

  Are much further apart.

  Move very quickly in all directions.
• What happens to particles when a substance changes state?

  The particles themselves stay the same.

  The way the particles are arranged changes.

  The way the particles move changes.
• What will a pure substance do?

  Melt and freeze at one specific temperature- the melting point.

  Boil and condense at one specific temperature- the boiling point.
• What does the amount of energy required for a substance to change state depend on?

  The amount of energy required to overcome the forces of attraction between the particles.
• The stronger the forces of attraction?

  The greater the amount of energy needed to overcome them.

  The higher the melting point and boiling point will be.
• What are substances that have high melting points due to strong bonds?

  Ionic compounds, metals and giant covalent structures
• In substances that contain simple molecules?

  The bonds between the molecules are strong covalent bonds.

  The forces of attraction between the molecules are much weaker.

  Only a little energy is needed to overcome the forces between the molecules, so the melting and boiling points are relatively low.
• What are the state symbols?

  (s) = solid

  (l) = liquid

  (g) = gas

  (aq) = aqueous (dissolved in water)
• What are the types of strong chemical bond?

  Ionic, covalent and metallic.
• What do ionic bonds occur between?

  Positive and negative ions.
• What do ions have?

  A complete outer shell of electrons
• What does ionic bonding involve?

  A transfer of electrons from metal atoms to non metals atoms.

  The metal atoms lose electrons to become positively charged ions.

  The non metal atoms gain electrons to become negatively charged ions.
• What is an ionic bond?

  A strong electrostatic force of attraction between the positive metal ion and the negative non metal ion.
• What are ionic compounds?

  Giant structures of ions
• What are ionic compounds held together by?

  Strong forces of attraction (electrostatic forces) that act in all directions between oppositely charged ions.

  I.e. ionic compounds are held together by strong ionic bonds.
• What are the properties of ionic compounds?

  They have high melting and boiling points.

  They do not conduct electricity when solid, because the ions cannot move.

  They conduct electricity when molten or in solution, because the charged ions are free to move about and carry their charge.
• What does metallic bonding occur in?

  Metallic elements.

  Alloys.
• What is the structure of metals?

  They have a giant structure in which electrons in the outer shell are delocalised (not bound to one atom and free to move)
• What is the arrangement of metals?

  A regular arrangement (lattice) of positive ions held together by electrostatic attraction to the delocalised electrons.
• What is a metallic bond?

  The attraction between the positive ions and the delocalised negatively charged electrons.
• What makes metals good structural materials?

  Metallic bonds are very strong.

  Most metals have high melting and boiling points.
• What can delocalised electrons do?

  Move around freely and transfer energy, this makes metals good thermal and electrical conductors.
• How are the particles in pure metals arranged?

  Regularly
• What can layers in metals do?

  Slide over each other quite easily, which means that metals can be bent and shaped.
• What are the uses of aluminium?

  High voltage power cables, furniture, drink cans and foil food wrap.

  This is because aluminium is corrosion resistant, ductile, malleable, low density and a good conductivity.
• What are the uses of copper?

  Electrical wiring, water pipes and saucepans.

  This is because copper is ductile, malleable and a good conductor.
• What are the uses of gold?

  Jewellery and electrical junctions.

  This is because gold is ductile, shiny and a good conductor.
• What are most metal objects made from?

  Alloys.
• What is an alloy?

  Mixtures (formulations) that contain a metal and at least one other element.
• What is the problem with pure metals?

  They are too soft for many uses.
• What does the added element in alloys do?

  Disturb the regular arrangement of the metal atoms so the layers do not slide over eachother so easily.
• What does the irregular arrangement of alloys mean?

  They are usually stronger and harder than pure metals.
• What is steel?

  A useful alloy made from iron
• How is iron produced?

  The reduction of iron (III) oxide in a blast furnace.
• Is molten iron pure?

  No, it contains roughly 96% iron and 4% impurities, including carbon, phosphorus and silica.
• What does irons impurity mean?

  It is very brittle and has limited uses.