Structures and Properties Flashcards
When does ionic bonding occur
When a metal and a non-metal react together
How does an ionic bond form
The metal (magnesium) loses (2) electrons and become cations The nonmetal (chlorine) each gain one electron and become anions so they all have full outer shell The positive ions are attracted to the negative ions and have an electrostatic attraction between them
Describe the bonding in an ionic compound
There is an electrostatic attraction between oppositely charged ions
When can ionic compounds conduct electricity? Why?
When they are molten or in an aqueous solution
The ions are free to move to their oppositely charged electrode and carry a charge
When can ionic compounds not conduct electricity and why
When they are solid
The ions are fixed in a giant lattice so the ions are not free to move to their oppositely charged electrode and carry a charge
Do ionic compounds have high or low boiling points, justify your answer
They have high boiling points because there are millions of strong electrostatic attractions between oppositely charged ions in the giant lattice which require a lot of heat energy to break them
Can ionic compounds be dissolved in water, justify your answer
Yes they can, water is a polar molecule which can break up the ionic lattice
Describe the structure of an ionic compound
A giant lattice that extends in all directions
Why are ionic compounds solid at room temperature
They have a high melting point as there are millions of strong electrostatic attraction between the ions in the giant lattice that take a lot of energy to break
Examples of simple molecules
Water, methane, carbon dioxide
Do simple molecules have high or low melting points, why
There are weak intermolecular forces between the molecules that take little energy to break up
Why do simple molecules not conduct electricity
There is no overall charge on the simple molecules so their neutral and therefore cant carry an electrical charge
Describe the bonding of a covalent molecule
There are strong covalent bonds between the atoms
Why do diamonds have high melting points
Diamonds have a macro molecular structure. There are millions of carbon atoms held by strong covalent bonds
Why might diamonds be used drill bits
They are real hard
Diamonds have a macro molecular structure. There are millions of carbon atoms held by strong covalent bonds so have a rigid structure
Why can’t diamonds conduct electricity
Each carbon atom is bonded to 4 other carbon atoms by strong covalent bonds so there are no delocalised electrons that can conduct electricity
Why does graphite have a high melting point
It has a macro molecular structure. Within each layer, each carbon atom us joined to 3 other carbon atoms by strong covalent bonds which take a lot of energy to break
Why can graphite conduct electricity
Within each layer of the structure, each carbon atom is joined by 3 other carbon atoms by strong covalent bonds. Therefore it has delocalised electrons which can carry charge through the structure and conduct electricity
Why is graphite soft
Graphite has a macro molecular structure which consists of layers. Each layer consists of millions of carbon atoms arranged in hexagons. Between the layers are weak intermolecular forces which can easily slide over each other making it very soft
What are fullerenes and potential uses
Large carbon molecules which have cage-like structures of different shapes. Can be used for drug delivery to specific parts of the body
What does aq mean
Aqueous - dissolved in water
What is the meaning of “nanowire”
Very small size
Nanoparticles are tiny… What does this mean
Have a high surface area to volume ratio
What is the structure of metals
Lattice - giant metallic structure arranged in closely packed regular layers
