C2- Bonding, Structure and Properties of Matter

• What is the structure of ionic compounds?

  A giant structure of ions
• What holds ionic compounds together?

  Strong electrostatic forces of attraction between oppositely charged ions
• How do the forces in ionic compounds act due to their structure?

  The forces act in every direction due to the 3D structure
• Give an example of an ionic compound.

  Sodium chloride (salt)
• What is covalent bonding?

  Covalent bonding is when atoms share one or more pairs of electrons
• Name some small molecules that have strong covalent bonds.

  HCl, H2, O2, Cl2, NH3, CH4
• What are polymers?

  Polymers are large covalently bonded molecules
• What are giant covalent structures?

  Giant covalent structures consist of many atoms covalently bonded in a lattice structure
• Give examples of giant covalent structures.

  Diamond and silicon dioxide
• How can diagrams represent covalent substances?

  Diagrams can use dot and cross, repeat units, ball and stick, and 2D/3D representations
• What is metallic bonding?

  Metallic bonding consists of positive ions and delocalised electrons arranged in a regular pattern
• What are delocalised electrons?

  Delocalised electrons are free to move through the metallic structure
• Why are metallic bonds strong?

  Because delocalised electrons are shared throughout the structure
• What are the three states of matter?

  Solid, liquid, and gas
• What happens at the melting point?

  Melting and freezing take place
• What occurs at the boiling point?

  Boiling and condensing take place
• How does particle theory explain changes of state?

  The amount of energy needed to change state depends on the strength of the forces between particles
• What determines the melting and boiling points of substances?

  The stronger the forces between the particles, the higher the melting and boiling points
• What are the limitations of the simple particle model?

  The model does not account for forces, represents particles as solid spheres, and lacks detail
• How are the states of matter represented in chemical equations?

  Solid (s), liquid (l), gas (g), and aqueous (aq)
• What are the properties of ionic compounds?

  Ionic compounds have regular structures, high melting and boiling points, and conduct electricity when melted or dissolved
• Why do ionic compounds conduct electricity when melted or dissolved?

  Because the ions are free to move and carry current
• Why can't ionic compounds conduct electricity when solid?

  Because the ions are fixed in place
• What are the properties of small molecules?

  Small molecules usually have low boiling and melting points and weak intermolecular forces
• What happens to intermolecular forces as the size of molecules increases?

  Intermolecular forces increase with the size of the molecules
• Why don't small molecules conduct electricity?

  Because small molecules do not have an overall electric charge
• What are the characteristics of polymers?

  Polymers have very large molecules linked by strong covalent bonds and are solids at room temperature
• What are giant covalent structures made of?

  Giant covalent structures consist of atoms linked by strong covalent bonds
• What are the properties of giant covalent structures?

  They are solids with very high melting points
• Name examples of giant covalent structures.

  Diamond, graphite, and silicon dioxide
• What are the properties of metals?

  Metals have giant structures of atoms with strong metallic bonding and high melting and boiling points
• Why can metals be bent and shaped?

  Because the layers of atoms in metals can slide over each other
• What are alloys?

  Alloys are made from two or more different types of metals
• How do the properties of alloys differ from pure metals?

  Alloys are harder than pure metals due to distorted layers in the structure
• Why are metals good conductors of electricity?

  Because delocalised electrons carry electrical charge through the metal
• Why are metals good conductors of thermal energy?

  Because energy is transferred by the delocalised electrons
• What is the bonding structure of diamond?

  Each carbon is joined to 4 other carbons covalently
• What are the properties of diamond?

  Diamond is very hard, has a very high melting point, and does not conduct electricity
• What is the bonding structure of graphite?

  Each carbon is covalently bonded to 3 other carbons
• Why is graphite soft and slippery?

  Because layers can slide over each other due to weak intermolecular forces