Covalent Bonding, Metallic Bonding and Ionic bonding, Properties of metals, nanoparticles Flashcards
What is covalent bonding?
When atoms share pairs of electrons. (strong bond)
Advantages of displayed formula
- quick and easy to draw and identify
- shows how they are bonded to each other
Advantages of ball and stick models
- shows the shape of the molecule
- 3D
- shows which atoms are bonded to which
Advantages of dot and cross diagrams
- shows which atoms are bonded to each other
- shows electrons
Disadvantages of displayed formula
- 2D
- cannot see electrons
Disadvantages of ball and stick models
- does not show electrons
- hard to draw when there are many atoms
Disadvantages of dot and cross diagrams
- does not show electrons orbiting
- hard to draw if there are many atoms
- 2D
Size of atom
1 nanometer (1x10^-9m)
Size of nucleus
About 1x10^-14m
Difference between simple and giant covalent structures
simple covalent structures have a fixed number of atoms (eg. ammonia) and giant covalent structures have large and variable amounts of atoms
Properties of giant covalent structures
- high boiling and melting points (strong intermolecular forces)
- strong (covalent bonds)
- cannot conduct electricity (except for graphite and graphene)
- has a lattice structure
- not soluble in water
Properties of simple covalent molecules
- low boiling and melting points
- weak intermolecular forces
- do not conduct electricity as they do not have an overall electric charge
What are polymers?
large molecules with many small repeating units called monomers that are joined with strong covalent bonds
What is graphene?
A single layer of graphite
Properties of graphene
- very high melting point
- very strong
- conducts electricity well due to having delocalised electrons
- often used in electronics and composites
What are fullerenes?
- Molecules of carbon atoms with hollow shapes
- based on hexagonal rings of carbon atoms but may also contain rings of five or seven carbon atoms
What was the first fullerene that was discovered?
Buckminsterfullerene (C60)
Properties of fullerenes
- low melting and boiling point (weak intermolecular forces
- cage like structure (can transport substances inside it eg. medicine)
- good catalyst (large surface area compared to volume)
- has a delocalised electron that can carry the charge
- lightweight
Are the intermolecular forces of polymers strong
yes, so they remain as solids at room temperature
How is ethene converted to polyethene?
the double covalent bond between the carbon atoms are broken and is joined to a neighboring molecule
Draw the shorthand way of representing a polymer
(see goodnotes)
Compare diamond to graphite
(see notability)
Where do we find metals on the periodic table?
on the left