C2 - Bonding, Structure and the properties of Matter Flashcards
Formation of ions, ionic bonding, ionic compounds, covalent bonding, simple molecular structures, allotropes of carbon, metallic bonding, states of matter, changing state, nanopartciles, uses of nanoparticles.
Formation of ions -
What are ions?
Charged particles
Formation of ions -
When are ions made?
When electrons are transferred
Formation of ions -
What happens when metals form ions?
lose electrons form + ions
Formation of ions -
What happens when non metals form ions?
Gain electrons form - ions
Ionic Bonding -
What is ionic bonding?
- Metal + non metal react.
- metal lose electron form positive ion
- non metal gain electrons form negative ions.
- opposite charge of ions are strongly attracted by electrostatic forces (called an ionic bond)
Ionic Bonding -
What is the name of the diagram used to represent ionic bonding?
dot and cross diagrams
Ionic Bonding -
What don’t dot and cross diagrams show?
- structure of compound
- size of ions
- how arranged
Ionic compounds -
What is the structure of an ionic compound?
Giant ionic lattice
Ionic compounds -
What is the structure in a giant ionic lattice?
-regular lattice
- strong electrostatic forces of attraction between oppositely charged ions
Ionic compounds -
What are the properties of ionic compounds?
- high melting and boiling point (many strong bonds between ions)
- when solid can’t conduct electricity
- when melted, ions free to move and carry electrical charge
- some dissolve in water (ions separate and free to move in solution so carry electrical charge)
Covalent bonding -
When does covalent bonding occur?
when non metals bod together + share pairs of electrons
Covalent bonding -
Why are covalent bonds very strong?
Positive nucleus of atoms attracted to the shared pair of electrons by electrostatic forces.
Covalent bonding -
What are the different ways of displaying covalent bonds?
- Dot and cross diagrams - electrons drawn in the overlap of the electron shells between those atoms.
- Displayed formula - shows covalent bonds as single lines between atoms
- 3D model - shows atoms, covalent bonds and their arrangement
Covalent bonding -
What are the + and - of the ways covalent bonds are displayed?
- Dot and cross diagrams:
+ show which atoms electrons come from - don’t show relative size of atoms
- how atoms arranged
- Displayed formula:
+ show how atoms connected in large molecules - don’t show 3D structure of molecules
- don’t show which atoms electrons come from
3D model:
+ shows atoms
+ shows covalent bonds and arrangement in space
- confusing for large molecules
- don’t show where electrons come from
Simple molecular substances -
What are simple molecular substances made up of?
Molecules containing a few atoms joined together by covalent bonds.
Simple molecular substances -
What are common examples of simple molecular substances?
-Hydrogen: 1 electron, one more to complete, form single covalent bonds
- Oxygen: need two more electrons, make double covalent bonds
- Methane: Carbon 4 outer shell electrons, forms 4 covalent bonds with hydrogen atoms
- Chlorine: 1 more electron, 2 chlorine atoms share pair electrons form single covalent bond
- Nitrogen: 3 more electrons, share 3 pairs electrons, triple covalent bond
-Water: oxygen shares pair electrons with two hydrogen atoms, form two single covalent bonds
- Hydrogen Chloride: Both atoms need 1 more electron.
Simple molecular substances -
Properties of simple molecular substances:
- covalent bonds
- very strong covalent bonds
- force attraction between molecules very weak.
- to melt/ boil need break feeble intermolecular forces not covalent bonds
- low melting and boiling points
- gases or liquids at room temp
- don’t conduct electricity (as not charged so no free electrons)
Polymers and Giant Covalent Structures -
What are polymers?
Long chains of repeating units
Polymers and Giant Covalent Structures -
How are atoms in polymers joined?
Strong covalent bonds
Polymers and Giant Covalent Structures -
What do you draw when drawing a polymer?
The repeating unit (shortest repeating section)
Polymers and Giant Covalent Structures -
How do you find the molecular formula of a polymer?
Write molecular formula of repeating unit in brackets and put an n outside
Polymers and Giant Covalent Structures -
Why are polymers solids at room temperature?
Intermolecular forces between molecules large so more energy to break bonds
Polymers and Giant Covalent Structures -
Why is the boiling point of a polymer lower than an ionic or covalent compound?
Intermolecular forces weaker between molecules
Polymers and Giant Covalent Structures -
What are giant covalent structures?
Macromolecules
Polymers and Giant Covalent Structures - How are giant covalent structures bonded?
Strong covalent bonds
Polymers and Giant Covalent Structures -
What are the properties of giant covalent structures?
- very high melting/ boiling points
- don’t conduct electricity (no charged particles)
Polymers and Giant Covalent Structures -
What are the examples of giant covalent structures?
- Diamond: 4 strong covalent bonds, rigid structure
- Graphite: 3 strong covalent bonds, layers of hexagons, each carbon atom one delocalised electron
-Silicon Dioxide or silica: sand, each grain one giant structure of silicon and oxygen
Allotropes of Carbon:
What are the allotropes of carbon and their properties:
Diamond - very hard, giant covalent structure, 4 covalent bonds, really, hard, very high melting, doesn’t conduct electricity.
Graphite - 3 covalent bonds, creates sheets carbon atoms arranged hexagons, soft, slippery (ideal lubricant), high melting point, delocalised electrons, conduct electricity + thermal energy.
Graphene - one layer of graphite, one atom thick (two dimensional substance), very strong, light (can be added to composite material to improve strength without increasing weight), delocalised electrons, conduct electricity, can be used in electronics.
Fullerene - molecules of carbon shaped like closed tubes/ hollow balls, carbon atoms arranged in hexagon/ pentagon/ heptagon, used to ‘cage’ other molecules, huge surface area (great industrial catalyst), lubricants, form nanotubes (tiny carbon cylinders).
Allotropes of Carbon -
What are the uses fullerenes and the first fullerene?
-deliver a drug into the budy
- industrial catalyst (huge surface area)
- lubricants
First fullerne;
- Buckminsterfullerene (C60)
- forms hollow sphere
Allotropes of Carbon -
What are nanotubes and their uses?
Nanotubes - tiny carbon cylinders
-ratio between their length and diameter is very high.
- conduct electricity and thermal energy
- high tensile strength (don’t break when stretched)
- nanotechnology - technology that uses very small particles such as nanotubes.
-nanotubes can be used in electronics, strengthen materials (without adding a lot of weight eg tennis racket).
Metallic Bonding -
What do all metals consist of?
A giant structure
Metallic Bonding -
What does metallic bonding involve?
Delocalised electrons
Metallic Bonding -
What happens during metallic bonding?
- electrons in outer shell of metal atoms delocliased. Strong electrostatic forces of attraction between positive metal ions and shared negative electrons.
- Forces of attraction hold atom in regular structure known as metallic bonding (very strong bonds)
Metallic Bonding -
What do substances that are held together by metallic bonding include?
Metallic elements and alloys
Metallic Bonding -
What produce all the properties of metals in metallic bonds?
Delocalised electrons
Metallic Bonding -
Why are most metals solid at room temperature?
-electrostatic forces strong so lots of energy to break bonds
- so have very high melting/ boiling points meaning most solid at room temperature
Metallic Bonding -
Why are metals good conductors of electricity and heat?
-delocalised electrons carry electrical charge + thermal energy through structure.
Metallic Bonding -
What does it mean if a metal is malleable?
Layers of atoms in metal slide over each other - mean can be bent, hammered, rolled into flat sheets.
Metallic Bonding -
Why are pure metals often not quite right for certain jobs?
- too soft
Metallic Bonding -
What happens when pure metals are mixed with alloys?
- Makes them harder
- new metal atom’s layers distored making it more difficult for them to slide over each other - makes them harder than pure metals
Metallic Bonding -
Why are alloys more helpful than pure metals?
They are harder
Metallic Bonding -
Why do the layers in a new metal atom made from two or metals become distorted?
Different elements have different sized atoms.
Metallic Bonding -
What is an alloy?
A mixture of two or more metals or metals and another element.
States of Matter -
What are the three states of matter?
solids, liquids, gases
States of Matter -
What does the state of something at a certain temperature depend on?
Strength of the forces of attraction between particles of material.
States of Matter -
How strong the forces of attraction in a material are depends on what?
- the material (structure of substance/ type of bonds holding particles together)
- temperature
- pressure
States of Matter -
What is the model called that is used to explain how the particles in a material behave in each three states of matter by considering each particle as small, solid, inelastic spheres?
Particle theory
States of Matter -
Solids:
- strong forces of attraction
- fixed positions
- regular lattice arrangement
- don’t move
- definite shape + volume (don’t flow)
- vibrate about their position (hotter they are the more they vibrate - meaning they expand slightly when heated)
States of Matter -
Liquids:
- weak force of attraction between particles
- random arrangement
- free to move past each other (stick closely together)
- constantly moving with random motion
- hotter the faster they move (causes them to expand slightly when heated)
States of Matter -
Gases:
- very weak forces of attraction
- free to move
- far apart
- travel in straight lines
- don’t keep definite shape or volume
- fill container
- move constantly + random
- hotter means faster
- expand when heated or their pressure increases
States of Matter -
Reality of the particle theory model:
-particles aren’t solid, inelastic or spheres
- doesn’t show forces between particles (don’t know how strong they are)
States of Matter -
What does aqueous mean?
Dissolved in water
Changing state -
What is it called when a solid turns into a liquid?
Melting
Changing state -
What is it called when a liquid turns into a gas?
Boiling
Changing state -
What is it called when a gas turns into a liquid?
Condensing
Changing state -
What is it called when a liquid turns to a solid?
Freezing
Changing state -
How do you predict the state of a substance?
- temperature below melting point of substance, it’s a solid
- temperature above boiling point, it’s a gas
- if it’s in between points it’s a liquid
Nanoparticles -
What is the diameter of a coarse particle and example?
2500 nm - 10,000 nm (dust)
Nanoparticles -
What is the diameter of a fine particle?
100nm to 2500 nm
Nanoparticles -
What is the diameter of a nanoparticle?
1 nm - 100 nm
Nanoparticles -
What are nanopartciles?
Particles that contain only a few hundred atoms
Nanoparticles -
What type of particles have a large surface area to volume ratio?
Nanoparticles
Nanoparticles -
Why is the surface area to volume ratio an important factor?
Can affect the way the particles behave
Nanoparticles -
How is surface area to volume ratio calculated?
surface area / volume = surface area to volume ratio
Nanoparticles -
What happens to the surface area as the size of a particle decreases?
Surface area increases in relation to volume - surface area to volume ratio increases
Uses of nanoparticles -
What are some uses of nanoparticles that have already been developed?
- catalyst (huge surface area to volume ratio)
- nanomedicine ( tiny particles absorbed more easily) -deliver drugs into cells when needed
- conduct electricity - tiny electric circuits for computer chips
- Silver nanoparticles have antibacterial properties - added ot polymer fibres for surgical masks + wound dressings + deodorants
- cosmetics - moisturisers (not oily)
Uses of Nanoparticles -
Why are nanoparticles contraversial?
- not tested to see long term effect on health
- should be clearly labelled on products
Uses of nanoparticles -
What are nanoparticles use din and why and effect?
Sun creams - better at protecting skin from UV rays
- better skin coverage
- not clear about effect on your body and health
- concerns that when washed away could damage environment
