Giant Covalent Structures Flashcards
What are allotropes
Different forms of the same element in the same physical state
How many carbon atoms is each atom linked to in diamond
Four other atoms
Why does diamond not conduct electricity
All electrons are fixed in covalent bonds between pairs of atoms
Why does diamond conduct thermal energy
The rigidity of strong covalent bonds mean as atoms get hotter and move faster the vibrations move rapidly throughout the structure
Uses of diamond
-cutting tools
How many carbon atoms is each atom linked to in graphite and how is it arranged
Covalently bonded to three other atoms arranged in hexagonal sheets
Why does graphite conduct electricity
Fourth outer shell electrons form a cloud of delocalised electrons that spread out over each layer and conduct electricity
Why is graphite soft
Weak London forces between sheets of atoms allows layers to Slide Over each other
Uses of graphite
-as a lubricant
-lining in furnace walls as can withstand high temperatures
What are composites
When two or more materials are combined to create a new material which has the desirable properties of both its constituents
What is buckminsterfullerene
First fullerene discovered and is C60 with a roughly spherical shape
-each carbon atoms bonded to three nearest neighbours
Why are fullerenes not giant covalent structures
As they are molecular forms of carbon
Why are fullerenes good electrical insulators
As the delocalised fourth outer shell electrons cannot move between molecules
Uses of fullerenes
-golf clubs
-vehicles for delivering drugs to specific body cells
What is graphene and its properties
-single layer of graphite
-extremely thin and strong
-good conductors of electricity and heat
