EL 7 (part 2) Flashcards
What is a compound?
Atoms of different elements which are chemically bonded
What is ionic bonding?
The electrostatic attraction between oppositely charged ions
What is metallic bonding?
The electrostatic attraction between positive metal ions and delocalised electrons
What substances have a macro molecular structure?
Polymers
What substances have a covalent network structure?
Some elements in group 4 and some of their compounds
What substances have a simple molecular structure?
- Some non-metal/non-metal compounds
What are the giant lattice structures?
Ionic, covalent network, metallic
What are the covalent molecular structures?
Simple molecular and macromolecular
Examples of ionic structures
Sodium chloride and calcium oxide
Examples of covalent network structures
Diamond, graphite, silica
Examples of metallic structures
Sodium, copper, iron
Examples of simple molecular structures
CO2, H2O, Cl2
Examples of macromolecular structures
Polythene, proteins, DNA
What type of particles do ionic structures contain?
Ions
What type of particles do covalent network structures contain?
Atoms
What type of particles do metallic structures contain?
Positive ions surrounded by delocalised electrons
What type of particles do simple molecular structures contain?
Small molecules
What type of particles do macromolecular structures contain?
Long-chain molecules
How are the particles in an ionic structure bonded together?
Strong ionic bonds between oppositely charged ions
How are the particles in covalent network structure bonded together?
Strong covalent bonds
How are the particles in a metallic structure bonded together?
Strong metallic bonds
How are the particles in simple molecular and macromolecular structures bonded together?
- Weak intermolecular bonds between molecules
- strong covalent bonds between the atoms within molecules
What is melting and boiling point like in ionic structures?
High
What is melting and boiling point like in covalent network structures?
Very high
What is melting and boiling point like in metallic structures?
Generally high (except mercury)
What is melting and boiling point like in simple molecular structures?
Low
What is melting and boiling point like in macromolecular structures?
Moderate - often decompose on heating
What is hardness like in ionic structures?
Hard but brittle
What is melting and boiling point like in covalent network structures?
Very hard (if three-dimensional)
What is melting and boiling point like in metallic structures?
Hard but malleable
What is melting and boiling point like in simple molecular structures?
Soft
What is melting and boiling point like in macromolecular structures?
Variable - many are soft but often flexible
What is electrical conductivity like in an ionic structure?
Electrolytes only conduct when molten or dissolved in water
What is electrical conductivity like in a covalent network structure?
Do not normally conduct - except graphite
What is electrical conductivity like in a metallic structure?
Conduct when solid or liquid
What is electrical conductivity like in a simple molecular and macromolecular structure?
Do not conduct
What is solubility in water like in ionic structures?
Often soluble
What is solubility in water like in covalent network structures?
Insoluble
What is solubility in water like inmetallic structures?
Insoluble (but some react)
What is solubility in water like in simple molecular structures?
Usually insoluble
- unless molecules contain groups which can hydrogen bond with water
What is solubility in water like in macromolecular structures?
Usually insoluble
What is solubility in non-polar solvents like in macromolecular structures?
Sometimes soluble
What is solubility in non-polar solvents like in simple molecular structures?
Usually soluble
What is solubility in non-polar solvents like in metallic structures?
Insoluble
What is solubility in non-polar solvents like in covalent network structures?
Insoluble
What is solubility in non-polar solvents like in ionic structures?
Insoluble
Why do metals have good electrical conductivity?
Delocalised electrons can move freely
Why are metals ductile?
The free movement of delocalised electrons allows atoms on layers to slide past each other