Topic 2.1 & 2.2 - Types of Materials & Bonding Flashcards
(36 cards)
What dictates the physical properties of a material?
The structure and bonding that exists within a material.
Key physical properties include melting/boiling point, malleability, hardness, and thermal/electrical conductivity.
Define structure in the context of materials.
How the particles (atoms, ions, molecules) are organised within the material.
What is bonding?
The force of attraction that holds particles together.
What are the three ways elements and compounds can be arranged?
- Monoatomic
- Molecules
- Lattices
What does ‘monoatomic’ mean?
Elements only consisting of one atom, such as noble gases (Group 8 elements).
What is a molecule?
A discrete cluster of two or more atoms chemically bonded together in a fixed quantity.
Provide examples of molecules.
- Oxygen (O2)
- Water (H2O)
Define lattices.
A regular repeating arrangement of atoms or ions chemically bonded in a fixed ratio.
What are examples of lattices?
- Sodium chloride (NaCl)
What is the goal of atoms when they bond?
To obtain stable valence shell (electron) configurations by achieving a full outer shell.
How can atoms achieve a full outer shell?
- Losing electrons
- Gaining electrons
- Sharing electrons
What are the two broad categories of bonding?
- Intramolecular
- Intermolecular
What is intramolecular bonding?
Forces of attraction within a molecule (or lattice), also known as primary bonding.
What types of bonding fall under intramolecular?
- Ionic
- Covalent (covalent molecular and covalent network)
- Metallic
What is intermolecular bonding?
Forces of attraction between molecules, also called secondary interactions.
What is the structure of metallic materials?
A continuous network of metal cations and a sea of delocalised electrons.
What is the structure of ionic materials?
A continuous network of cations and anions that combine in a fixed ratio.
What characterizes covalent network materials?
A continuous network of atoms that combine in a fixed ratio.
What characterizes covalent molecular materials?
Individual molecules.
What determines the melting point of a material?
The strength of the bonds holding it together.
What happens at the melting point?
The intermolecular/intramolecular forces of attraction are overcome, allowing particles to separate and move.
How do primary bonds compare to secondary interactions in terms of melting point?
Primary bonds are strong and result in a high melting point, while secondary interactions are weak and produce a low melting point.
What is the electrical conductivity of a material?
A measure of the ability of electric charge to flow through the structure of a material.
What is the electrical conductivity of metallic materials?
High, due to the presence of delocalised electrons.
