C2.3 Properties of materials

• What is a key property of carbon that allows it to form many different compounds?

  Carbon can form four covalent bonds.
• What is diamond like in terms of structure?

  Diamond has a strong covalent structure with each carbon atom bonded to four others.
• What is graphite like in terms of bonding?

  Graphite has layers of carbon atoms bonded by weak forces, allowing them to slide over each other.
• What are graphene and fullerenes?


  Graphene is a single layer of carbon atoms arranged in a hexagonal lattice, while fullerenes are spherical arrangements of carbon atoms.
• Why do some materials conduct electricity?

  Materials conduct electricity when they have free-moving charged particles, such as electrons or ions.
• Why might some substances not conduct electricity?

  Substances may not conduct electricity if they lack free-moving charged particles.
• Why do buckyballs have unique properties?

  Buckyballs have unique properties due to their spherical structure and the arrangement of carbon atoms.
• What happens when substances change state?

  • Bonds between particles are broken or formed.
  • Energy is absorbed or released during the process.
  • The state can change from solid to liquid, liquid to gas, etc.
• What is the melting point of bromine?

  • 7°C
• What is the state of bromine at 25°C?

  Bromine is in the liquid state at 25°C.
• What is the boiling point of bromine?

  59°C
• What is the state of calcium at 25°C?


  Calcium is in the solid state at 25°C.
• What is the state of calcium at 30°C?

  Calcium is in the solid state at 30°C.
• What is the state of calcium at 700°C?

  Calcium is in the liquid state at 700°C.
• What is sublimation?


  • Sublimation is the process where a substance changes directly from solid to gas.
  • It occurs without passing through the liquid state.
  • Examples include dry ice and iodine.
• Why do some substances have high boiling points?

  Substances with strong intermolecular forces or covalent bonds typically have high boiling points.
• What is a bulk property?

  A bulk property is a characteristic that results from the behavior of many atoms acting together.
• Why do covalent structures have high melting points?

  Covalent structures have high melting points due to the strong bonds between atoms that require significant energy to break.
• Why are ionic compounds brittle?

  Ionic compounds are brittle because when force is applied, like charges repel, causing the structure to shatter.
• Why do metals conduct electricity?

  Metals conduct electricity due to the presence of free-moving electrons that can carry charge.
• Why do polymers not conduct electricity?

  Polymers do not conduct electricity because they lack free-moving charged particles.
• Why does graphite conduct electricity?

  Graphite conducts electricity due to the presence of delocalized electrons that can move freely between layers.
• Why do ionic compounds conduct electricity in solution?

  Ionic compounds conduct electricity in solution because the ions are free to move and carry charge.
• What are the properties of nanoparticles?

  • Nanoparticles are typically 1-100 nanometers in size.
  • They have a high surface area to volume ratio.
  • They can exhibit different properties compared to bulk materials.
• What are some possible risks of nanoparticles?

  Nanoparticles may be harmful to health and the environment due to their small size and potential toxicity.
• Why do nanoparticles have different properties than bulk materials?

  Nanoparticles have different properties due to their small size and the increased surface area to volume ratio.
• What is the significance of the surface area to volume ratio in nanoparticles?

  A high surface area to volume ratio in nanoparticles enhances their reactivity and strength.
• What is the size range of nanoparticles?

  Nanoparticles range from 1 to 100 nanometers in size.
• What is an example of a property that changes in nanoparticles compared to bulk materials?

  Silver appears white in bulk but is transparent when in nanoparticle form.
• What is a potential application of nanoparticles?

  Nanoparticles can be used in drug delivery systems due to their small size and ability to penetrate cells.
• Why might scientists be concerned about the use of nanoparticles?

  Scientists are concerned that nanoparticles may pose unknown health risks due to their small size and potential toxicity.