SC7 - Types of Substance Flashcards
What is a molecule?
A compound joined together by covalent bonds
What are intermolecular forces?
Forces between molecules
How well does a covalent, simple molecular structure conduct electricity?
In a simple molecular structure, electricity cannot flow as there are no free electrons and the molecules have no overall charge.
What are monomers?
They are simple molecules which can be made into chains to form a polymer.
What is an allotrope?
A different structural form of an element.
What are fullerenes?
They are allotropes of carbon which have 1 carbon covalently bonded to 3 carbons.
They can be spherical or tubular and have weak intermolecular forces, so they have low melting points. Due to them having weak forces, they are soft and slippery.
What is graphene?
Graphene is a sheet of carbon with no fixed formula. They have weak intermolecular forces making them slippery and soft. But they are usually one atom thick, making them the lightest known material. They also have free electrons to move across their surface making it very conductive.
Give 2 giant structures of carbon and their properties.
Diamond - Has a rigid network of carbon with a tetrahedral arrangement where 1 carbon is connected. to 4 other carbons. It is very strong and is used in cutting tools.
Graphite - Has 1 carbon connected to 3 others it also has layers. This means it has delocalised electrons making it more conductive.
They both have very high melting and boiling points.
What are the properties of metals?
Solids with high melting points
Shiny
Malleable
High density
Conductive
What are the properties of non-metals?
Solids/liquids/Gases with low melting points
not usually shiny
brittle
low density
poor conductor
What is metallic bonding?
It is the electrostatic connection between positive and negative delocalised electrons.
Describe the structure of metals
Ate stacked in layers with a sea of delocalised electrons. It also has a giant lattice of positive metal ions.
Why are metals malleable?
Because when they are hammered the layers slide over each other and they don’t get shattered
How do metals conduct electricity?
The electricity is free to move across the sea of delocalised electrons.
What are the 3 bonding models?
Dot and Cross (covalent)
Metallic bonding
Ball and stick (molecular)
