Bonding and Properties of Matter Flashcards
what ion do group 1 form? (metal)
+1 ion
what ion do group 2 form? (metal)
+2 ion
what ion do group 6 form? (nonmetal)
-2 ion
what ion do group 7 form? (nonmetal)
-1 ion
what is covalent bonding
the sharing of electrons between 2 non metals
what is ionic bonding
the transfer of electrons from a metal to non metal
describe the properties of pure metals & why they are like this
- conduct electricity & heat easily (delocalised electrons can carry the electrical current/thermal energy)
- soft (have layers meaning they can slide across each other)
describe the properties of alloy metals & why they are like this
- hard (have distorted layers so cannot slide across each other)
what is the structure of ionic compounds
- giant ionic lattice
describe the properties of ionic compounds & why they are like this
- high melting and boiling point (have many bonds so takes lots of energy to break them)
- only conducts when molten or dissolved (ions must be free to move)
describe the properties of simple covalent compounds & why they are like this
- low melting/boiling points (molecules joined by strong covalent bonds but held together by weak forces thatre easily broken)
- dont conduct electricity (2 non metals so no delocalised electrons)
give examples of simple covalent compounds
- H2O
- CO2
- HCl
give examples of ionic compounds
- MgO
- NaCl
- KBr
give examples of alloy metals
- steel
- brass
- bronze
- gold (in jewellery)
give examples of pure metals
- gold
- silver
- sodium
give examples of giant covalent compounds
- fullerenes ie buckminsterfullerene
- graphite
- diamond
- silica
describe the properties of giant covalent compounds & why they are like this
- high metling/boiling points
- do not conduct electricity
- do not dissolve
what is the structure of diamond
- giant covalent structure
- made of pure carbon
- each carbon bonded to 4 other atoms
describe why the properties of diamond make it useful
- very hard bc of the many bonds
- we can use it in drills
describe why the properties of graphite make it useful
- layers of graphene slide over each other weak forces btwn the layers so is very soft
- conducts electricity (delocalised electrons move through the graphite, carrying charge)
- v.high melting/boiling point (lots of v. strong covalent bonds so lots of energy needed to break them)
- we use it for lubricants and pencils
what is the structure of graphite
- made of layers of graphene
- made of pure carbon
- each carbon makes 3 bonds with other atoms
compare the properties of buckminsterfullerenes and carbon nanotubes
- both: pure carbon, make 3 carbon bonds, hard, used for drug delivery
- buckminsterfullerene used for reinforcements in buildings
what are polymers
- Polymers are very large molecules made when many smaller molecules join together, end-to-end
- Alkenes can be used to make polymers.
- smaller molecules are called monomers
- lots of monomer molecules → a polymer molecule
give uses of certain polymers
- polyethen used for plastic bags and bottles
- polypropene used for crates and ropes
- polychloroethene used for water pipes and insulation on electricity cables
give examples of alkenes forming polymers
Alkenes can act as monomers because they have a double bond:
Ethene can polymerise to form poly(ethene),AKA polythene.
Propene can form poly(propene), AKA polypropylene.
compare properties of polymer chains with cross links and without cross links
- polymers with cross links (cannot slide across each other: fixed in place, burn upon heating)
- polymers without cross links (can slide across each other so melt upon heating))
what is nanotechnology
- rearranging/ manipulating atoms to make other useful structures
- about 100 nanometres across.
describe the properties of nanotechnology & why they are like this
- high surface area to volume ration (as you get smaller, you increase surface area)
- strong forces btwn surfaces/ reactive(Atoms on the surface of a material more reactive than in the centre, so a larger SA means the material is more reactive.)
what are the uses of nano technology
- sports equipment: added to materials to make them stronger whilst being lighter. used in tennis rackets
- clothing: silver nanoparticles added to socks, stopping them from absorbing foot odour as the nanoparticles have antibacterial properties
- healthcare: used in sunscreens,offering protection and can be rubbed in so there are no white marks.
what are the concerns about nanopartilces
Harmful effects
- may be able to enter the brain from the bloodstream and cause harm(toxic).
- Some people think more tests should take place before nanoparticles of a material are used on a wider scale.
