S2.4 From models to materials SL

Question 1

Insulating

Answer 1

Property of a substance that has a high resistance to thermal or electrical conductivity.

Question 2

Bonding continuum

Answer 2

Bonding is seen as a continuum spanning ionic, covalent, and metallic models, illustrated by a triangle. This model shows transitions between bonding types, acknowledging substances with intermediate characteristics.

Question 3

What are the characteristics of ionic bonding?

Answer 3

Ionic bonding is marked by electrostatic attraction between oppositely charged ions, leading to properties like brittleness and high melting points.

Question 4

How does metallic bonding affect material properties?

Answer 4

Metallic bonding, featuring delocalized electrons, results in materials being malleable and conductive.

Question 5

What influences the properties of covalent materials?

Answer 5

Covalent materials’ properties, such as hardness and electrical conductivity, vary significantly based on the atoms involved and their bonding, making prediction complex.

Question 6

Bond type of Potassium and Aluminium

Answer 6

Metallic

Question 7

Bond type of Water

Answer 7

Polar Covalent

Question 8

Bond type of Magnesium hydride and Sodium chloride

Answer 8

Ionic

Question 9

Bond type of Silicon and Oxygen

Answer 9

Covalent

Question 10

How to determine a compound’s bonding triangle position with electronegativity data?

Answer 10

Use average and difference in electronegativity between elements to plot on the triangle, classifying the bond as ionic, covalent, or metallic.

Question 11

How does a compound’s position in the bonding triangle predict its properties?

Answer 11

Near the ionic corner indicates higher melting points and water solubility. Closer to covalent means softer with lower melting points.

Question 12

Alloys

Answer 12

Homogeneous mixtures of a metal and other metals or non-metals.

Question 13

How do alloys differ from their base metals in structure and properties?

Answer 13

Alloys include a base metal and additional elements, altering the metallic lattice. This can introduce elements of different sizes (substitutional alloys) or fill gaps (interstitial alloys), leading to properties like increased hardness or altered melting points.

Question 14

How do the properties of alloys relate to non-directional bonding?

Answer 14

Alloy properties are influenced by non-directional, metallic bonding with delocalized electrons. This allows stress distribution without direction specificity. The inclusion of different elements affects malleability, hardness, and melting point due to this bonding nature.

Question 15

Polymers

Answer 15

Large molecules, or macromolecules, made by combining smaller compounds called monomers.

Question 16

What composes plastics and defines their structure?

Answer 16

Plastics are composed of polymers, which are large molecules made from repeating units called monomers.

Question 17

What are the key characteristics of plastics?

Answer 17

Plastics are flexible, durable, moldable, lightweight, and have insulating properties.

Question 18

Why are plastics flexible and durable?

Answer 18

The flexibility and durability of plastics are due to the ability of polymer chains to slide past one another and the covalent bonds within polymer chains.

Question 19

What gives plastics their ability to be molded into shapes?

Answer 19

The moldability of plastics is due to the intermolecular forces between polymer chains that allow them to be shaped under heat and pressure.

Question 20

Why do plastics have low density and poor conductivity?

Answer 20

Plastics’ low density and poor conductivity are related to the types of atoms in the polymer chains and the lack of electron delocalization.

Question 21

Addition polymerisation

Answer 21

Forming a polymer by breaking a double bond in each monomer, which then create new bonds linking the monomer units together.

Question 22

How to represent the repeating unit of an addition polymer from monomers?

Answer 22

Identify monomers with double/triple carbon bonds. Polymerization breaks these bonds, linking monomers with single bonds to form the polymer chain.

Question 23

How to deduce a monomer from an addition polymer structure?

Answer 23

Analyze polymer’s repeating units. Each represents a monomer that had a reactive double/triple bond, allowing deduction of the monomer’s original structure.