Bonding Flashcards
Between which types of particles does ionic bonding occur?
Metal and non metal
Describe ionic bonding
Atoms lose or gain electrons to get full outer shells. They form ions which are strongly attracted to one another due to their opposite charges
Which groups of atoms want to lose or gain electrons?
Atoms in group 1 and 2 want to lose electrons and atoms in group 6 and 7 want to gain electrons. Atoms in group 0 already have full outer shells so are unreactive
What are the features of ionic bonds?
structure, state, boiling/melting points, solubility, conductivity, rigidity, density
- Regular lattice structure with strong bonds
- Solid at room temperature
- High melting/boiling points
- Dissolve in water
- Conduct electricity in solution
- Hard but brittle
- Dense
Between which types of particles does metallic bonding occur?
Between two metals
Describe metallic bonding
Atoms lose electrons to gain full outer shells, and the electrostatic attractions between the positive metal ions and the negative electrons hold them together in a regular structure
What are the features of metallic bonds?
structure, melting/boiling points, solubility, conductivity, rigidity, density, properties of metal
- Regular lattice structure with strong bonds
- Solid at room temperature
- Very high melting/boiling points- strong forces of attraction between bonds, requiring more energy to break them
- Don’t dissolve in water
- Good conductors- free electrons can move to carry on electrical currents
- Hard but malleable and ductile
- Dense
- Shiny- free electrons mean the metal is strongly bonded so the ions are closely packed so light reflects
- Sonorous and heavy- closely packed ions
What are alloys?
Mixtures of metals used to create desirable properties
Between which types of particles does covalent bonding occur?
Between two non metals
Describe covalent bonding
Atoms share electrons to gain full outer shells
How many electrons does each covalent bond provide to each atom?
One
What are the features of simple molecular covalent bonds?
structure, state, boiling/melting points, solubility, conductivity, rigidity, density
- Strong covalent bonds but weak intermolecular forces
- Liquid or gas at room temperature
- Low melting/boiling points
- Don’t dissolve in water
- Don’t conduct electricity
- Hard but brittle
- Not dense
What are the features of giant covalent lattices?
structure, state, boiling/melting points, solubility, conductivity, rigidity, density
- Regular lattice structure with strong bonds
- Solid at room temperature
- High melting/boiling points
- Don’t dissolve in water
- Don’t conduct electricity (except graphite)
- Hard but brittle
- Dense
What causes high melting/boiling points?
The stronger the bonds, the more energy needed to break them, so the higher the melting/boiling points are
What causes solubility?
Ionic bonds dissolve easily as the ions separate and are free to move so they carry an electrical current
What causes brittleness?
Bonds break under pressure and don’t reform
What causes ductility?
Layers in metal slide past each other but the free electrons move with them so the bonds don’t break
What are nanoparticles?
Really small particles of 1-100 nanometres across
What are fullerenes?
Fullerenes are molecules of carbon shaped like hollow balls or closed tubes arranged in hexagons, and due to the fact they have lots of covalent bonds, they are very strong and are used as reinforcement
What are some uses of nanoparticles?
- Making sensors detecting one type of molecule
- Making stronger, lighter building materials
- Nanomedicine- delivering drugs into cells as they are easily absorbed
What are smart materials and what are their uses?
- Behave differently depending on conditions they were formed in
- Nitinol is a shape memory alloy used in braces and glasses frames
Whatare the features of a thermosoftening polymer?
- Weak intermolecular forces of individual tangled chains which are free to slide over each other
- No crosslinking between chains means it’s easy to melt the plastic
- Can be melted & remoulded many times
What are the features of a thermosetting polymer?
- Strong intermolecular forces hold the chains firmly together
- Crosslinks mean it doesn’t soften when heated making it hard, strong and rigid
