Structures Flashcards
Give four properties of giant Ionic lattices
- soluble in water
- high melting point
- conducts electricity when liquid
- crystalline
Give two examples of giant Ionic lattices
Sodium chloride
Magnesium oxide
Give four properties of simple Covalent / Covalent molecular structures
- low melting and boiling points (tend to be mainly gases)
- not soluble in water
- do not conduct electricity
- soft when solid
Give two examples of simple covalent / covalent molecular structures
Iodine and carbon dioxide
Give three properties of giant covalent structures
- Very high melting and boiling point
- Diamond does not conduct electricity, graphite and graphene do
- insoluble in water
Give a property of Graphite
Slippery soft solid
Give a property of graphene
100 times stronger than steel but is very thin, light and inexpensive
Draw diamond
-
Draw Graphite
-
Draw and label Graphene
-
Give four properties of a giant metallic structure
High mpt/bpt
Conducts heat and electricity
Ductile (can be stretched into wires)
Malleable (bends)
List three main properties of Ionic compounds
- crystalline
- high melting point
- conducts electricity when liquid
Sodium chloride conducts electricity when molten but not when solid, explain why?
The electrons have become delocalised and the ions are free to move and therefore carry charge
Why do ionic compounds have high melting and boiling points ?
Due to the strong electrostatic forces of attraction between oppositely charged ions which require a lot of energy to break
Why can’t some substances conduct electricity as a solid?
The ions are in a fixed position
Why do simple covalent structures/molecular covalent structures have low melting/boiling points?
Due to the weak forces of attraction between the molecules (van der Waals) despite that there are strong covalent bonds between the atoms in the molecule
Why does diamond not conduct electricity?
It has 4 carbon atoms surrounding each carbon atom and therefore has no free electrons
Why does Graphite conduct electricity?
It has a free electron which can carry charge
Why is Graphite slippery?
It is in forms of layers which can slide over each other due to weak van der Waals
Why do some metallic structures have high melting points and boiling points?
Strong metallic bonds require a lot of energy to break
Why do metallic structures conduct heat/electricity?
They have delocalised electrons which have a lot of kinetic energy to move and carry the charge/energy
Why are metallic structures malleable?
The sea of electrons allows the layers of ions to slide over each other without disrupting the bonding when a force is applied
How many atoms of carbon surround each carbon atom in Graphite?
3
Why do diamond and Graphite both habe high melting points?
They have strong covalent bonds in all directions which require a lot of energy to break
Which of graphite’s properties means that it can be used as a lubricant ?
It’s weak van der Waals enable layers to slide over one another
Why is it that Graphite can conduct electricity?
Carbon is covalently bonded to three carbon atoms. This leaves one free electron per atom to carry current
Lead is malleable because (2)
- The result of tightly packed atoms cause the outer electrons to delocalised
- and allow the layers of ions to slide over one another without disrupting the bonding
Why can metals produce wire shapes?
They are ductile and have delocalised electrons which allow ions to slide over each other
Define alloy
A mixture of two or more elements at least one of which is a metal, and the resulting mixture has metallic properties
What is meant by the term ductile ?
Can be stretched into wires
Explain fully how a single covalent bond forms
Shared pair of electrons
Explain why metals conduct electricity
The electrons have become delocalised and the ions are free to move and therefore carry a charge
Describe the bonding and structure in a typical metal like sodium. Use a labelled diagram
(Metal ions and free electrons from outer shells of metal atoms)
The bonding in metals is metallic and it gives a giant metallic lattice. The metallic bond is the attraction between regularly arranged positive metal ions and delocalised electrons
Why does HCL have a low boiling point?
Weak van der Waals forces between the molecules, meaning there is little energy required to break the bonds
Show the equation for working out the % of gold in an alloy
Number of carats divided by 24 x 100
Use of diamond
- Cutting of tools
Draw a diagram of an alloy
- Positive Ions
- Different sized ions
- Negative delocalised electrons
Give an example of an alloy
- Steel is an alloy of iron and carbon
Why are alloys harder than metals (2)
- The different sizes of atoms in an alloy distort the layers in the metallic structure
- Making it more difficult for the layers of ions to slide over each other
What is gold used in jewellery usually an alloy of ?
- An alloy with silver, copper and zinc
Uses of Graphene
- Batteries
- Solar cells
