Studied by 0 peopleWhat sort of force do ionic compounds have that keep them together?
Strong electrostatic intermolecular force
What are ionic compounds?
Giant structures of ions
Can simple (covalent) molecules conduct electricity?
No because the molecule has no overall charge
How are atoms in a polymer held together?
Strong covalent bonds, intermolecular forces
What are the three states of matter?
Solid, liquid, gas
What is the name of the temperature a pure substance melts and freezes at?
Melting point
What is a metallic bond?
The attraction between the positive ions and the delocalised electrons
Do metals have high or low melting and boiling points?
High
Why can pure metals be easily shaped?
The particles have a regular arrangement so the layers can easily slide over each other
Why do simple (covalent) structures have low melting and boiling points?
Because they have weak intermolecular forces between molecules that are overcome easily
What is the structure of graphite?
A layered, hexagonal lattice
What was the first fullerene to be discovered?
Buckminsterfullerene
What is the name of the temperature a pure substance boils and condenses at?
Boiling point
What happens at the forces of attraction increase?
The more energy needed to overcome the forces of attraction so the higher the melting and boiling point
What substances have high melting and boiling points due to strong bonds?
Ionic compounds, metals and giant covalent structures
What are the three types of bonding?
Covalent, ionic and metallic
Which type of substance gives away electrons in ionic bonding?
The metal
What type of substances does ionic bonding involve?
Metal and non-metal
Why does ionic bonding work?
Because they end up with opposite charges so they attract each other
Why do atoms in ionic bonding transfer electrons?
To gain a full outer shell
How are ionic compounds held together?
strong electrostatic forces of attraction
Are ionic compounds boiling and melting points high or low?
High
Why are ionic compounds boiling and melting points high?
Because ionic compounds contain strong ionic bonds that require a lot of energy to overcome
Can ionic compounds conduct electricity?
only in liquid
Why can ionic compounds only conduct electricity when molten?
Because the charged ions are free to move about and carry their charge
What sort of substances does metallic bonding occur in?
Metallic elements and alloys
Why do metals have high melting and boiling point?
Because metallic bonds are strong and so need a lot of energy to overcome them
Why are metals good thermal and electrical conductors?
Because the delocalised electrons can move around freely and transfer energy
What is an alloy?
Mixtures that contain a metal and at least one other element
Why do we use alloys?
Pure metals are too soft for many purposes
Why are alloys harder than pure metals?
Because adding another element disrupts the regular arrangement so the layers don't slide over each other
What is a covalent bond?
A shared pair of electrons between atoms
What type of substances does covalent bonding occur in?
Non-metallic elements and compounds
Are covalent bonds strong or weak?
Strong
Do simple (covalent) structures have high or low boiling and melting points?
Low
If a (covalent) molecule is larger, will the intermolecular forces between molecules be stronger or weaker?
Stronger
What is a giant covalent structure?
All the atoms are linked by strong covalent bonds
What is diamond a form of?
Carbon
What is the structure of diamond?
A giant covalent lattice
How many bonds does each carbon atom make in diamond?
4
Why does diamond have a high melting point?
The are many strong covalent bonds so a lot of energy would be needed to overcome them, bonded with many carbons
Does diamond conduct electricity?
No because there are no delocalized electrons
How many bonds does each carbon atom make in graphite?
3
how are the layer of graphite held together?
Weak intermolecular forces
Why is graphite soft?
The weak intermolecular forces between layers allow the layers to slide over each other
Why can graphite conduct heat and electricity?
Because there is one delocalised electron per atom
What is graphene?
A single layer of graphite
What are the properties of graphene?
Very strong, good thermal and electrical conductor, nearly transparent
What is a fullerene?
A covalently bonded form of carbon that contains different numbers of carbon atoms
What shapes do fullerenes form?
Hollow shapes including balls, tubes and cages
How many carbon atoms does buckminsterfullerene have?
60
What is the structure of buckminsterfullerene?
The atoms are joined together in a series of pentagons and hexagons
Why is buckminsterfullerene the most stable fullerene?
It is the most symmetrical
What are carbon nanotubes?
Cylindrical fullerenes
What are the functions of fullerenes?
To deliver drugs in the body, in lubricants, as catalysts, for reinforcing materials
What are plastics?
Man-made polymers
Why are polymers a solid at room temperature?
Because the intermolecular forces are strong
An ionic compound forms a (structure)
giant lattice structure of ions
Ionic compounds are held together by
strong electrostatic forces of attraction between oppositely charged ions.
Ionic compounds properties
High melting and boiling point, DOESN’T conduct electricity when solid, DOES conduct electricity when in a solution or molten, brittle
Ionic compounds have high melting and boiling points because
of strong electrostatic forces of attraction between oppositely charged ions which require a lot of energy to break.
Ionic compounds don’t conduct electricity when solid because
the ions are not free to move so they cannot carry charge, and therefore conduct electricity.
Ionic compounds do conduct electricity when molten and in solutions because
the ions are free to move so they can carry charge and therefore conduct electricity
Ionic compounds are brittle because
when an ionic lattice forced ions of the same charge line up so they repel, breaking up the layers of lattice.
Ionic compounds are soluble in
water
As the charges of ions increase the melting and boiling point
increase because the ions have a stronger attraction making it harder to break the bonds.
When atoms share a pair of electrons they form a
covalent bond
Covalent bonds are always
strong.
Covalent bonding occurs in
non-metallic elements and in compounds of non metals.
You draw covalent bonds with
dot and cross diagrams
The positively charge nuclei of covalently bonded atoms are attracted to
the shared pair of electrons by electrostatic forces.
Bonds occur within a molecular are
intramolecular
Intermolecular forces are
between molecules
Simple covalent molecules have (between molecules)
weak intermolecular forces between molecules
Covalent bonds has low melting and boiling points because
the weak intermolecular forces require little energy to overcome.
When a covalently bonded substance melts the strong covalent bonds are
not overcome and stay the same.
Intermolecular forces increase with
the size of the molecules
The bigger the molecule the
higher the melting and boiling points. (But they are still relatively low)
Simple covalent molecules do not conduct electricity because
there are no delocalised electrons to carry charge, because all electrons are used in the strong covalent bonds.
Simple covalent molecules have
low melting and boiling points, they cannot conduct electricity
Atoms in polymers are linked to the other atom by
strong covalent bonds
Polymers have
very large molecules
Polymers are solid at room temperature because
the intermolecular forces between polymer molecules are relatively strong (the bigger the molecule, the stronger the intermolecular forces)
Most giant ionic structures (like diamonds) cannot conduct electricity because
each carbon atom has 4 strong covalent bonds so there are no free electrons so diamonds cannot conduct electricity.
Most giant ionic structures (like diamond) have high melting and boiling points because
there are many strong covalent bonds which form a giant covalent structure, and these bonds take a lot of energy to overcome.
Most giant ionic structures (like diamond) are strong and hard because
there are many strong covalent bonds.
Graphite can conduct electricity because
there is one delocalised electron which is not held in strong covalent bonds.
Graphite has a very high melting and boiling point because
there are many strong covalent bonds which require a lot of energy to break
Graphite is slippery because
there are weak forces between the layered structure so the layers can slide.
Graphene is a
single layer of graphite
Fullerene is
simple molecules of carbon atoms with hollow shapes which is based on hexagonal rings. Each atom has 3 strong covalent bonds and 1 delocalised electron.
Fullerene is a good lubricant because
they can roll and have weak intermolecular forces
Ionic bonding is the
transfer of electrons to form ions by electrostatic interaction
Ions are
charged particles
Metal ions always
lose electron/s and are positive
Non metal ions always
gain electron/s and are negative
Ionic bonding occurs between
metals and non metals
Ions in ionic bonding are held together by
electrostatic attraction
polymer diagram
Note
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