Structure and Properties

Created by

Olivia

Cards (71)

What are the ions in a compound arranged in?
A giant ionic lattice
What is a giant ionic structure also known as?
A giant ionic lattice
What do giant ionic lattices result in?
The formation of a crystal
What is a crystal?
A solid containing particles joined together to form a regular pattern
What do strong electrostatic forces between molecules lead to? 
A great deal of energy needed to separate the positive and negative ions in a crystal lattice
What do ionic compounds have?
High melting and boiling points
What do solid ionic compounds not do?
Conduct electricity
Why do strong ionic compounds not conduct electricity?
As their ions are held firmly in place
What can the ions not do in a strong ionic compound?
They can’t move to conduct an electric current
What happens when an ionic compound melts?
The ions are free to move
Whats the difference between solid and molten ionic compounds?
Molten can conduct electricity , solid can’t
What does this show?
A giant ionic lattice
What does a solution of an ionic compound in water do?
It also conducts electricity
Why do ionic compounds have high melting and boiling points?
Due to the strong electrostatic attraction between oppositely charged ions requires lots of energy to break
What are the two different types of covalent bonded substances?
Simple molecules and giant structures
What do simple covalent molecules contain?
Only a few atoms held together by covalent bonds
Although the covalent bonds holding the atoms together are strong the intermolecular forces are weak
What are the properties of simple molecular substances?
Low MP and BP
Don’t conduct electricity
Why do simple molecular substances have a low MP and BP?
Weak intermolecular forces
Why can’t simple molecular substances conduct electricity?
No free electrons or an overall electric charge
What are some examples of simple molecules?
Hydrogen, ammonia, methane and pure water
What do simple molecules have?
Strong covalent bonds between atoms and weak intermolecular forces
What’s the nature of simple molecular substances?
Soft
What happens when covalent substances melts or boils?
The weak intermolecular forces break, not the strong bonds
What are simple molecular substances at room temperature?
Gases, liquids or solids with low MP and BP
How are strong bonds represented in diagrams?
Lines
How are weak intermolecular forces represented in diagrams?
Dashed lines or dotted lines.
What do giant covalent structures contain?
Very many atoms each joined to adjacent atoms by covalent bonds
What are the atoms usually arranged like in giant covalent structures?
In giant regular lattices which are extremely strong
What are allotropes?
A different form of the same in element in the same state
What are examples of the allotropes of carbon?
Diamond, graphite, graphene, fullerenes
What are the properties of giant covalent structures?
High melting points
Variable electrical conductivity
Why do giant covalent structures have high melting points?
As lots of strong covalent bonds must be broken
Why do giant covalent structures have variable electrical conductivity?
Some can conduct and some cannot e.g diamond cant conduct electricity
What is graphite?
A form of carbon in which the carbon atoms form covalent bonds with three other carbon atoms
How many covalent bonds does graphite have?
Three
Why can graphite conduct electricity?
It has a delocalised electron which can carry a charge
Why is graphite soft?
It contains layers of carbon atoms which can slide over each other
What is graphite much softer than?
Diamond
What can graphite be used in?
Pencils and lubricants