Bonding Flashcards
What is ionic bonding?
The electrostatic force of attraction between oppositely charged ions
How are ions formed?
Ions are formed when atoms lose or gain electrons
What type of ions do metals form?
Positive ions because they lose electrons
What type of ions do non-metals form?
Negative ions because they gain electrons
What are compound ions?
Ions made up of a group of atoms with an overall charge
What is the structure of ions?
They have a giant ionic lattice
What are the properties of ionic compounds?
They have:
- high melting points
- conduct electricity when molten or dissolved
- tend to dissolve in water
How would you prove if a substance is ionic?
- dissolve the substance in water
- add a cathode and anode into the solution with a bulb in the circuit
- if the solution conducts electricity(bulb switches on), then it is ionic
- if insoluble melt the substance
How would you determine which ionic compound has a higher melting point?
Charge determines which ionic compound has a higher melting point, not the size
What happens down the group as the ions become larger?
Charge density decreases
What is charge density?
The ratio of the charge of an ion to its volume
Which are the five common compound ions?
sulfate-SO4^2- hydroxide-OH- nitrate-NO3- carbonate-CO3^2- ammonium-NH4+
What is a covalent bond?
A single shared pair of electrons
What is the structure of diamond?
Giant covalent
Tetrahedral
Carbon makes 4 covalent bonds
What are the properties of diamond?
Very high melting point
Hard
insoluble
Non-conductor of electricity(the outer electrons are held in localised bonds)
What is the structure of graphite?
Giant covalent
Planar- arranged in layers
Carbon makes 3 covalent bonds
What are the properties of graphite?
High melting point
Conducts electricity(each carbon has one delocalised electron)
Slippery-the layers can slide over each other easily
(used in pencils and as a dry lubricant)
Soft
Insoluble
Which forces bond together the layers of graphite?
Weak van der Waals forces
What is the structure of iodine?
Molecular covalent
What are the properties of iodine?
Low boiling and melting point
Poor conductor of electricity(no charged particles)
What is dative covalent bonding?
A covalent bond where both of the shared pair of electrons come from one atom
What are the common examples of dative covalent bonding?
NH4+
H3O+
NH3BF3
What is metallic bonding?
The electrostatic force of attraction between the positive metal ions and the delocalised electrons
What is the structure of metallic bonding?
A giant metallic lattice
What are the properties of metals?
High melting point
Good thermal and electrical conductors
Soft, ductile and malleable
Arranged in layers
How does the number of delocalised electrons per atom affect the melting point?
The more delocalised electrons there are per atom, the stronger the bonding and the higher the melting point
What happens to the metallic bonding strength going down a group?
Going down a group, the ions become larger, the charge density decreases and the weaker the metallic bonding
How many bonding and lone pairs are there in a LINEAR molecule and what is the bond angle of the molecule?
Bonding pairs - 2
Lone pairs - 0
Bond angle - 180