C2 - Bonding and Structure

• What are compounds?

  Substances in which 2 or more elements are chemically combined
• How many types of strong chemical bonds are there?

  Three types
• What are the three types of strong chemical bonds?

  Ionic, covalent, and metallic
• What are the particles in ionic bonds?

  Oppositely charged ions
• In what type of compounds do ionic bonds occur?

  Compounds formed from metals combined with non-metals
• What defines covalent bonding?

  Atoms share pairs of electrons
• Where does covalent bonding occur?

  In most non-metallic elements and in compounds of non-metals
• What is the characteristic of metallic bonding?

  Atoms share delocalised electrons

  
• What charge do non-metal atoms acquire in ionic bonding?

  They become negatively charged ions
• What charge do metal atoms acquire in ionic bonding?

  They become positively charged ions
• What electronic structure do ions produced in ionic bonding achieve?

  They have the same electronic structure as a noble gas
• How can electron transfer during the formation of an ionic compound be represented?

  By a dot and cross diagram

  
• What holds ionic compounds together?

  Strong electrostatic forces of attraction between oppositely charged ions
• What is covalent bonding characterized by?

  Atoms sharing one or more pairs of electrons
• What is the structure of ionic compounds?

  A giant structure of ions
• What are polymers?

  Large covalently bonded molecules
• How do the forces in ionic compounds act due to their 3D structure?

  The forces act in every direction
• Give an example of an ionic compound.

  Sodium chloride (salt)

  
• Name some small molecules that have strong covalent bonds.

  HCl, H2, O2, Cl2, NH3, CH4
• What are giant covalent structures also known as?

  Macromolecules
• Give examples of giant covalent structures.

  Diamond, silicon dioxide
• How can diagrams of covalent substances be represented?

  Dot and cross, repeat units for polymers, ball and stick, and 2D/3D diagrams
• What does metallic bonding consist of?

  Positive ions and delocalised electrons arranged in a regular pattern

  
• What is the delocalised electron system in metallic bonding?

  The electrons ‘lost’ from the atoms to form positive ions

  
• What is the characteristic of delocalised electrons in metallic bonding?

  They are free to move through the structure
• Why are metallic bonds considered strong?

  Because delocalised electrons are shared through the structure

  
• What are the three states of matter?

  Solid, liquid, and gas
• At what point do melting and freezing occur?

  At the melting point
• At what point do boiling and condensing occur?

  At the boiling point
• How does particle theory explain changes in states of matter?

  It explains melting, boiling, freezing, and condensing
• What does the amount of energy needed to change state depend on?

  It depends on the strength of the forces between the particles
• What factors influence the nature of the particles in a substance?

  The type of bonding and the structure of the substance
• How do stronger forces between particles affect melting and boiling points?

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

  There are no forces, all particles are spheres, and the spheres are solid
• How are the three states of matter represented in chemical equations?

  Solid (s), liquid (l), gas (g), and aqueous (aq)
• What type of structures do ionic compounds have?

  Regular structures known as giant ionic lattices
• Why do ionic compounds have high melting and boiling points?

  Because a lot of energy is required to break the strong bonds
• When can ionic compounds conduct electricity?

  When melted or dissolved in water
• Why can't ionic compounds conduct electricity when solid?

  Because the ions are fixed in place
• What states are substances with small molecules usually found in?

  Gases or liquids