4.8 Materials

• Atoms in crystalline materials are arranged in a regular, repeating pattern.
• Match the state of matter with its atomic/molecular arrangement:

  Solids ↔️ Tightly packed in a regular pattern

  Liquids ↔️ Loosely packed with some order

  Gases ↔️ Randomly distributed with large distances
• The physical properties of a material can be observed without changing its chemical composition.
• The melting/boiling point of a material is the temperature at which it changes state
• The physical properties of a material depend on its atomic structure
• What does elasticity describe in mechanical properties?

  Return to original shape
• Match the atomic structure with an example:

  Crystalline ↔️ Metals, ceramics

  Amorphous ↔️ Glasses, polymers
• The rigid and brittle nature of crystalline materials is due to their regular, repeating atomic pattern
• Amorphous materials have a gradual transition during their melting point.
• Amorphous materials exhibit greater elastic and plastic deformation.
• Crystalline materials have higher thermal conductivity than amorphous materials.


  True
• Amorphous materials are typically good electrical conductors.

  False
• Amorphous materials like glass are strongly magnetic.

  False
• What type of magnetism do crystalline materials typically exhibit?

  Strong
• Why do crystalline materials exhibit strong magnetic properties?

  Regular atomic pattern
• Match the optical property with its definition:

  Transparency ↔️ Allows light to pass through

  Reflectivity ↔️ Ability to reflect light

  Refractive Index ↔️ Bends or refracts light
• Arrange the following atomic orders from most ordered to least ordered:

  1️⃣ Long-range order in crystalline materials

  2️⃣ Short-range order in amorphous materials
• Water is an example of a liquid state of matter.

  True
• Match the physical property with its definition:

  Density ↔️ Mass per unit volume

  Melting Point ↔️ Temperature at state change

  Electrical Conductivity ↔️ Ability to conduct electricity
• Crystalline materials are strong but less elastic and less plastic
• Arrange the steps explaining why crystalline materials are rigid and brittle.

  1️⃣ Regular, repeating atomic pattern

  2️⃣ High strength

  3️⃣ Low elasticity
• Crystalline materials have good electrical conductivity due to their regular atomic patterns
• Match the crystalline material with its magnetic property:

  Iron ↔️ Strong magnetic properties

  Glass ↔️ Non-magnetic
• Match the material property with its characteristic in crystalline or amorphous materials:

  Transparency ↔️ Generally more transparent in amorphous materials

  Reflectivity ↔️ Higher in crystalline materials
• Amorphous materials have long-range order in their atomic arrangement.

  False
• An example of a liquid is water, gasoline, or mercury.
• Match the physical property with the type of material:

  Density ↔️ Generally higher in crystalline materials

  Melting Point ↔️ Depends on the specific material

  Electrical Conductivity ↔️ Varies based on atomic structure
• What is electrical conductivity the ability of a material to do?

  Conduct electricity
• Amorphous materials have sharply defined melting/boiling points.

  False
• Crystalline materials have higher strength but are less elastic
• What influences the physical properties of materials in different states?

  Atomic/molecular arrangement
• The physical properties of a material depend on its atomic structure
• Arrange the following characteristics to describe the atomic structure and properties of crystalline and amorphous materials:

  1️⃣ Crystalline: Regular, repeating pattern

  2️⃣ Crystalline: Rigid, brittle nature

  3️⃣ Amorphous: Random, disordered arrangement

  4️⃣ Amorphous: Flexible, malleable behavior
• Crystalline materials have higher strength compared to amorphous materials.
• The random arrangement of atoms in amorphous materials results in lower thermal conductivity.
• The electrical conductivity of a material is influenced by its atomic structure.
• Iron is an example of a magnetic crystalline material.
• Glass, ceramics, and most plastics are magnetic materials.

  False
• Why are amorphous materials typically non-magnetic?

  Disordered atomic arrangement
• Crystalline materials are generally more transparent than amorphous materials.

  False