Chapter 2
Metallic bonding
Giant metallic lattice structure
Contains a sea of delocaliezd electrons that bonds the cations and anions
Tightly packed
electrostatic attraction between the cations and sea of delocalized electrons
Properties
Good electrical conductors
sea of delocalized electrons are able to carry electrical charges
Malleable and ductile
arranged in a regular lattice structure
When external force is applied, the layers of cations slide over each other resulting in the metal to bend and be malleable
Ionic Bonding
Giant Ionic Lattice structure
Regular arrangement of alternating cations and anions
Held together by strong ionic bonds
When more electrons are transferred from the metal to the non-metal atom, the electrostatic attraction between the ions become stronger
Properties
High melting and boiling points
Large amount of energy is required to overcome the strong electrostatic attraction between the oppositely charged ions
Good conductor of electricity
Molten state
In molten state, ions break out of the lattice structure and are free to move
mobile electrons carry electric charges, conducting electric current through the molten liquid
Solid state
Ions are held in fixed positions
No mobile ions to carry electric charge
High solubility in water
Covalent Bonds
A pair of electrons is shared between two atoms leading to a perfect valence shell
Properties
Poor electrical conductivity
No free-moving ions or electrons present to carr the electric charges
Low melting and boiling points
Small amount of energy is required to overcome the weak intermlecular forces of attraction
When a simple molecule melts, it is the weak intermolecular frces that are overcome.
Low solubility in water
Mostly insoluble in wtaer except for organic solvents
covalent bonding
Giant covalent structure
Also known as macromolecules
Graphite
Each carbon atom bonded to three other carbon atoms
Structure
Flat hexagonal layers
Weak forces of attraction hold layers together
Properties
Soft and slippery
Small amount of energy is required to overcome the weak intermolecular forcess of attraction between the layers
Layers are able to slide over each other easily when a force is applied which allows it to be a good lubricant
Good electrical conductor
Each carbon atom has an outer electron that did not take part in bonding
High melting and boiling point
large amount of energy is required to overcome these numerous, strong covalent bonds
Diamond
Consists of carbon atoms
Structure
Tetrahedral structure
Properties
Very hard
Very high melting point
A large amount of energy is required to overcome the strong covalent bonds between atoms
Non-conductor of electricity
All outer electrons are used in bonding
Silicon Dioxide
structure
Tetrahedral arrangement of atoms
Properties
very hard
Very high melting point
Large amount of energy is required to overcome the strong covalent bonds
Non-conductor of electricity
All valence electrons were used in bonding so there are no mobile electrons to conduct electricity