1.5 Solid Structures Flashcards
The Coordination Number
Of an ion gives the number of its nearest neighbours
Ionic solids are made of …
Giant lattices of positive and negative ions
How are the physical properties of an ionic structure decided?
Via the structure and bonding of the ionic compounds
Giant lattices often have four different typical characteristics these are:
High melting temperature, Often soluble in water, Hard but brittle, Poor electrical conductivity when solid.
Giant Covalent Solids
Are solids that consists of networks of covalently bonded atoms that stretch throughout the whole structure
Allotropes
Are two different forms of the same element in the same state. E.g. Graphite and diamond
What are the physical properties of Diamond?
Very high melting temperature, Extremely hard, Insoluble in water, poor conductor of electricity
How many times is each carbon covalently bonded to another in diamond?
Four other carbons
What are the physical properties of Graphite?
Very high melting temperature, Soft slippery feel, Insoluble in water, Good conductor of electricity, low density
What is the carbon structure like in graphite?
Layers of Hexagonal rings, in between each line are delocalised electrons
How many times is each carbon covalently bonded to another in graphite?
Three other carbons
Delocalised
Means that an electron is not attached to a particle atom - it can move around between atoms
Simple molecular solids
Have covalent bonds within molecules held together by weak intermolecular forces
What are the physical properties of simple molecular solids?
Low melting and boiling temperatures, Soft, Normally insoluble, Poor conductors
What are two common examples of simple molecular solids?
Ice and Iodine
