Chemistry Bonding Structure and the Properties of Matter

What is a compound?

A substance in which two or more elements are chemically combined.

What are the three types of chemical bonds?

• Ionic​

• Covalent​

• Metallic​

Describe ionic bonding.

• Involves transfer of electrons from metal atoms to non-metal atoms.​

• Forms positively charged metal ions and negatively charged non-metal ions.​

• Results in electrostatic attraction between oppositely charged ions.​

What is a giant ionic lattice?​

• A regular structure extending in all directions in an ionic compound.​

• Held together by strong electrostatic forces between oppositely charged ions.

List properties of ionic compounds.

• High melting and boiling points due to strong electrostatic forces.​

• Do not conduct electricity when solid (ions fixed in place).​

• Conduct electricity when molten or dissolved (ions free to move).​

Explain covalent bonding.​

• Involves sharing pairs of electrons between non-metal atoms.​

• Forms molecules with strong bonds between atoms.​

What are the properties of small covalent molecules?

• Low melting and boiling points due to weak intermolecular forces.​

• Do not conduct electricity (no free ions or electrons).

Describe metallic bonding.​

• Positive metal ions surrounded by a sea of delocalized electrons.​

• Strong electrostatic attraction between ions and electrons.​

What are the properties of metals due to metallic bonding?

• High melting and boiling points.​

• Good electrical and thermal conductivity.​

• Malleable and ductile.

How does the structure of diamond relate to its properties?

• Each carbon atom covalently bonded to four others.​

• Very hard with a high melting point.

• Does not conduct electricity (no free electrons).

Describe the structure and properties of graphite.

• Each carbon atom bonded to three others, forming layers.​

• Layers held together by weak forces, allowing them to slide (lubricant).​

• Conducts electricity due to delocalized electrons.

What are fullerenes?

• Molecules of carbon atoms with hollow shapes (e.g., buckyballs, nanotubes).​

• Used in drug delivery, lubricants, and as catalysts.

Define nanoparticles.

• Particles between 1-100 nanometers in size.​

• Contain a few hundred atoms.

What are some applications of nanoparticles?

• Medicine (drug delivery).​

• Electronics.​

• Cosmetics (e.g., sunscreens).​

• Catalysts.

What are the properties of giant covalent structures?

• High melting and boiling points (strong covalent bonds).

• Do not conduct electricity (except graphite and graphene).

• Insoluble in water.

What is graphene, and what are its properties?

• A single layer of graphite (one atom thick).

• Very strong due to covalent bonding.

• Extremely light and flexible.

• Conducts electricity due to delocalized electrons.

What are polymers, and how does their structure affect their properties?

• Large molecules made of repeating monomer units.

• Strong covalent bonds hold atoms together in chains.

• Intermolecular forces vary:

  • Weak forces → flexible, low melting points.

  • Strong forces (e.g., cross-linking) → rigid, high melting points.

What are alloys, and why are they stronger than pure metals?

• Mixtures of metals (or metal + non-metal).

• Different-sized atoms distort the layers of metal atoms.

• Prevents layers from sliding over each other easily, making alloys harder than pure metals.

How do nanoparticles compare to bulk materials?

• Much larger surface area to volume ratio.

• More reactive and efficient as catalysts.

• Different optical, electrical, and chemical properties.

What are potential risks of nanoparticles?

• May enter the body and cause unknown long-term health effects.

• Potential environmental impact (accumulation in ecosystems).

• More research needed to understand safety concerns.

How does temperature affect the movement of particles in solids, liquids, and gases?

• Higher temperature → more kinetic energy → faster movement.

• Solids: Vibrate faster.

• Liquids: Move more freely.

• Gases: Move rapidly and spread out.

What is meant by "bulk properties" of materials?

• Properties that depend on the structure and bonding of a substance.

• Example: Density, conductivity, melting and boiling points.

How do forces between particles change during melting and boiling?

• Melting: Particles gain energy and overcome some intermolecular forces.

• Boiling: Particles gain enough energy to completely break free from intermolecular forces.

How do the properties of simple molecules differ from giant covalent structures?

• Simple molecules: Low melting/boiling points due to weak intermolecular forces.

• Giant covalent structures: High melting/boiling points due to strong covalent bonds.

What is the difference between thermosoftening and thermosetting polymers?

• Thermosoftening: Soften when heated, weak intermolecular forces, can be reshaped.

• Thermosetting: Do not soften when heated, strong cross-links, rigid structure.

What are limitations of the simple model of the atom?

• There are no forces

• All particles are represented as spheres

• The spheres are solid