Chemistry - Physical Properties of Chemicals

Properties of ionic and metallic substances, molecular substances, polymers, and covalent networks.

Ionic Substance - Melting and Boiling Point

Ionic substances generally have high melting and boiling points due to the strong electrostatic forces of attraction between oppositely charged ions. Therefore a large amount of heat energy is required to break them.

Ionic Substance - Solubility

The solubility of an ionic substance depends on the polarity of the solvent.

Ionic substances are soluble in polar solvents, such as water, because the force of attraction between ions and water is stronger than the attraction between oppositely charged ions. They are insoluble in nonpolar solvents, as there is no strong attraction to separate the ions.

Ionic Substance - Density

Generally high density as the ions tend to be held closely together due to the strong ionic bonds between ions.

Ionic Substance - Thermal Conductivity

Good thermal conductors as the ions are closely packed together in a lattice allowing for heat energy to be easily transferred through the vibration of ions.

Ionic Substance - Electrical Conductivity

Electrically conductive in molten and aqueous state, as the ions (charged particles) are able to move past each other and carry a current.

They do not conduct as a solid as ions are in fixed positions and cannot move to carry a current.

Ionic Substance - Malleability/Brittleness

Brittle due to strong directional ionic bonds preventing ions from moving past each other without breaking. When a force is applied, the layers shift causing same-charge ions to end up next to each other and repel.

Ionic Substance - Hardness/Softness

Hard due to strong electrostatic attraction holding ions in a 3D lattice, preventing layers from sliding over each other.

Ionic Substances - Particles, Forces, Structure

Particles: ions - cations and anions'

Forces: ionic bond - strong directional electrostatic forces of attraction between oppositely charged ions

Structure: Held in a 3D lattice of alternating cations and anions

Metallic Substances - Melting and Boiling Points

Generally high melting points because of the metallic bonds as strong forces of attraction exist between cations and the delocalised electrons. Therefore a large amount of heat energy is required to break them.

Metallic Substance - Solubility

Insoluble in water as forces of attraction between metal atoms is stronger than forces of attraction between metal atoms and water.

Metallic Substance - Density

High density as the atoms have large masses and are held closely together by the strong metallic bonds, and electrons are able to move.

Metallic Substance - Thermal Conductivity

Good thermal conductors as the metal ions are closely packed together in a lattice allowing for heat energy to be easily transferred through the vibration of metal ions. Free moving electrons also add to the conductivity of thermal energy.

Metallic Substance - Electrical Conductivity

Good electrical conductors/Electrically conductive as they have free moving ions - delocalised electrons, allowing electrical current to be carried.

Metallic Substance - Malleability/Brittleness

Malleable due to the non-directional bonding allowing metal atoms to move past each other without breaking the metallic bonds.

Metallic Substance - Hardness/Softness

Variable, but normally hard due to the strong electrostatic attraction between metal cations and delocalised electrons.

Alloys are hard due to the different sized atoms added, disrupting the lattice and preventing layers from sliding over each other.

Metallic Substance - Particles, Forces, Structure

Particles: Metal atoms (metal cations and delocalised electrons)

Forces: Metallic bonds - strong non-directional electrostatic forces of attraction between metal cation and delocalised electrons.

Structure: Held in a 3D lattice of metal cations in a sea of delocalised electrons.

Molecular Substance - Melting and Boiling Points