Structure and bonding Flashcards
How are ionic bonds formed?
Metal atoms donate electrons to non-metal atoms
What is the charge on the metal ion?
Metal ions have a positive charge
What is the charge on the non-metal ion?
Non-metal ions have a negative charge
Describe the structure of the giant ionic lattice and state what holds ionic compounds together
Giant ionic lattice: a regular structure containing massive numbers of particles that continues in all directions throughout the structure
Strong electrostatic forces of attraction hold the ionic compound together
Explain why ionic solids have high melting and boiling points
Many electrostatic forces of attraction have to be overcome. A lot of energy has to be used to overcome these forces
Do ionic substances conduct electricity? Explain your answer
Solid ionic compounds do not conduct electricity. When molten (melted) or dissolved in water the ions dissociate, can move and carry the charge
What is a molecule? Give examples of covalent bonded molecules
A molecule is a particle made from atoms joined together by covalent bonds
How is a covalent bond formed?
Non-metals atoms share electrons
What are intermolecular forces?
Intermolecular forces are weak forces between molecules
Molecules have low melting points, why?
Molecules are not bonded to each other. Only the weak inermolecular forces have to be overcome so little energy is required
Do molecules conduct electricity?
Molecules do not conduct electricity as there is no free electrons/ions to carry the charge
What is polymer?
A polymer is a long chain molecule made from joining lots of small molecules together
What is a thermosoftening polymer?
Thermosoftening polymer has no bonds between polymer chains that softens when heated
Name 3 giant covalent structures.
Diamond
Silicone dioxide
Graphite
Why does graphite conduct electricity and diamond does not?
Diamond does not have any free electrons or ions so doesn’t conduct electricity.Graphite has free electrons that can move and carry the charge
Why do metals conduct electricity?
Metals conduct electricity because the delocalised electrons can move freely and carry the charge
Why do metals have high melting and boiling points?
Very strong attraction between the positive metal ions and the negative electrons is hard to overcome and this takes a lot of energy
What is an alloy and why is it harder than a pure metal?
An alloy is a mixture of a metal with small amounts of other elements added, usually other metals. Alloys are hard as the layers are distorted and can no longer slide over each other
What are nanoparticles and what are they used for?
Nanoparticles are structures between 1 and 100nm in size, typically containing a few hundred atoms, Nanoparticles are used in drug delivery, sun creams, cosmetics, deodorants and electronics
Graphene, fullerene and carbon nanotubes are all examples of nanoparticles. Give examples of what each one can be used for
Graphene: Electronics and carbon fibre
Fullerene: Drug delivery, catalyst
Carbon nanotubes: Make items stronger e.g. tennis rackets
