C3- Structure and bonding Flashcards
2 assumptions about particle model
2 key facts when we change the temp of the model
Solid spheres of identical size
No forces between particles
-Size and shape stays same
-Energy changes, faster if hotter
3 limitations of the particle model
-Particles aren’t solid
-Particles aren’t spherical
-There are forces between the particles
Solid particle model
spacing?
forces?
energy?
motion?
compression?
shape?
Closely packed
Strong forces between
Low energy
Vibrate about fixed positions
Can’t be compressed
Fixed shape
Liquid particle model spacing?
forces?
energy?
motion?
compression?
shape?
Closely packed
Medium forces between
Medium energy
Can slide over each other
Can’t be compressed
Fills container bottom
Gas particle model
spacing?
forces?
energy?
motion?
compression?
shape?
Spread out
Weak forces between
High energy
Free, random motion
Can be compressed
Fills whole container
Metallic bonding Defintion
Strong force of attraction between positive metal ions and negative delocalised electrons
Metallic bonding
Structure
A giant lattice of metal ions with delocalised electrons
Metallic bonding
Melting point
High melting point, strong electrostatic attraction between metal ions and delocalised electrons, takes high energy to break
Metallic bonding
Electrical conductors
Good electrical conductors, delocalised electrons can carry charge through the lattice
Metallic bonding
Thermal conductors
Good thermal conductors, delocalised electrons move through the lattice transferring thermal energy
Alloy definition
A mixture of two or more elements, one of which is a metal
Are alloys soft and why?
Alloys are harder than pure metals because of the irregular pattern of dif sized atoms
Ionic bonding
Definition
The strong force of electrostatic attraction between positive ions and negative ions
Ionic bonding is between…
Metals and non-metals
Ionic bonding
Structure
Giant lattice of cations and anions
Ionic bonding
Melting point
High melting point, strong forces of attraction between ions of opposite charge, takes lots of energy to break
Ionic bonding
Thermal conductors
Poor conductors, no free electrons
Ionic bonding
Electrical conductors
Conducts electricity when dissolved or molten as the ions are free to move
Covalent bonding
Definition
Strong electrostatic forces between a shared pair of electrons and the nuclei
Covalent bonding is between…
Non-metals
Simple covalent bonding
Structure
Simple structure with a fixed number of two or more atoms joined together
Simple covalent molecule
Bonding
Strong covalent bonds between atoms
Weak intermolecular forces between molecules
Simple covalent bonding
Melting point
Low melting point, weak intermolecular forces need little energy to overcome
Simple covalent bonding
Electrical conductors
Do not conduct electricity, they have no free electrons
Simple covalent bonding
Thermal conductors
Poor conduction, they have no free electrons
Giant covalent structure
Structure
Giant structure with a variable number of atoms
Diamond
Structure?
Melting point?
Electrical conductor?
Thermal conductor?
Giant 3d structure, each atom to 4 other carbon
High melting point, strong covalent bonds
Insulator, no free electrons
Thermal conductor, through the layers
Graphite
Structure?
Melting point?
Electrical conductor?
Thermal conductor?
Giant layers, each atom to 3 other carbon
High melting point, strong covalent bonds
Good conductor as has delocalised electrons
Graphene
Structure?
Melting point?
Electrical conductor?
Thermal conductor?
Giant layer with each atom to 3 other carbon
High melting, strong covalent bonds
Good conductor as has delocalised electrons
Fullerenes
Structure?
Melting point?
Uses?
Simple hollow 3d molecules
Variable, strong covalent in each shape, weak between shapes
Carry drugs in body, as catalysts, as lubricants
Nanoscience
The study of particles between 1-100nm in size
Nanoparticle
Diameter (nm)
1-100
Fine particle
Symbol
Diameter(nm)
PM2.5
100-2500
Coarse particle
Symbol
Diameter(nm)
PM10
2,500-10,000
Why are nanoparticles more effective than materials in bulk?
They have a high surface area to volume ratio, so a higher percentage of atoms are exposed at the surface. So smaller quantities are needed.
Dot and cross diagram
Ads and dis
Ad- Clear where electrons come from
Dis- Shows the electrons to be still
Structural formula
Ad & Dis
Ad- Shows the bonds between atoms
Dis- Can’t tell where electron came from
Ball and stick diagram
Ad and Dis
Ad- Shows ions as 3 dimensional
Dis-Shows too much space
Inter molecular forces definition
Weak force of attraction between molecules in a covalent structure
Uses of nanoparticles
Dangers of nanoparticles
Sun creams, cosmetics, medicine, catalysts
Could absorb into skin and affect living cells or harm aquatic life
