BONDING, STRUCTURE AND PROPERTIES OF MATTER Flashcards
What are ions?
Charged particles
What happens when metals form ions?
Lose electrons to form positive ions
What happens when non-metals form ions?
Gain electrons to form negative ions
What is ionic bonding?
When a metal and non-metal react together
The metal atom loses electrons and the non-metal gains electrons
How do you show ionic bonding?
Dot and cross diagrams
Brackets with + or 2-
What structure do ionic compounds have?
Giant ionic lattice structure
What properties do ionic compounds have?
High melting and boiling points
Can’t conduct electricity when solid however when dissolved they can as ions are free to move
What is covalent bonding?
When non-metal atoms bond together and share pairs of electrons
Why are covalent bonds very strong?
Because the positive charged nuclei of the bonded atoms are attracted to the shared pair of electrons by electrostatic force
What structure do substances containing covalent bonds usually have?
Simple molecular structures
What are the properties of simple molecular structures?
Very strong covalent bonds
Forces of attraction are very weak
Low melting and boiling points
Don’t conduct electricity
Why don’t simple molecular structures with covalent bonds conduct eletricity?
Because there are no free electrons/ions
What are the properties of giant covalent structures?
Strong covalent bonds
Very high melting and boiling points
Don’t conduct electricity
What is the structure of diamond?
Giant covalent structure
Each carbon atom forms four covalent bonds
What is the structure of graphite?
Each carbon atom forms three covalent bonds to create layers of hexagons
Each carbon atom has one delocalised electron
What are the properties of diamond?
Very hard as 4 strong covalent bonds on each carbon
Very high melting point
Doesn’t conduct electricity as no free electrons/ions
What are the properties of graphite?
Soft and slippery as no bonds between layers
High melting point
Can conduct electricity as delocalised electron
What is graphene?
One layer of graphite
What are the properties of graphene?
Covalent bonds make it strong
Light
Conducts electricity
What are fullerenes shaped like?
Molecules of carbon shaped like close tubes or hollow balls
What can fullerenes be used for?
To cage other molecules to e.g. deliver a drug into the body
Industrial catalysts
What are properties of fullerenes - surface area?
Large surface area
What are nanoTUBES?
Fullerene (tiny carbon cylinder)
Conducts electricity and thermal energy (heat)
Strong
What is metallic bonding?
Electrons in outer shell of a metal are delocalised
Strong forces of electrostatic attraction between positive metal ion and shared negative electrons
Forces hold the atoms together in a regular structure
What are the properties of metals (metallic bonding)?
High melting and boiling points as strong bonds
Conduct electricity due to delocalised electron
Can be bent/hammered/rolled as layers can slide over each other
Why are alloys harder than pure metals?
Different elements have different sizes atoms
When another element is mixed with a pure metal layers of metal atoms are distorted
So it is more difficult for them to slide over each other
What happens when a solid is melted then boiled?
Heated so particles gain more energy
They vibrate which weakens forces
Particles then have enough energy to break free from their positions
Then heated more till enough energy to break their bonds
What happens when a gas is condensed then frozen?
Gas cools so particles don’t have enough energy to overcome forces of attraction
Bonds form
Less energy so more bonds form till held in place
What are nanoparticles diameter?
They have a diameter between 1nm and 100nm
What is the surface area to volume ratio of a nanoparticle?
surface area / volume
