metallic bonding Flashcards
list the properties of metallic compounds
hard, malleable, ductile, shiny/lustrous, high boiling point, good conductors of heat/electricity, high density, sonorous and forms cations in reactions
what does the density of a metallic compound depend on
mass of ions, ion radius, and how they are packed/arranged (usually tightly)
describe an alloy
- created my melting substances and then mixing them together (carbon - other metals etc)
- two types - substitutional and interstitial
- more durable and less corrosive then actual metals
- usually harder then other metals, lower melting points (other particles weaken the metallic bonds), not as malleable/ductile, less electrical conductivity, more brittle
describe a crystal and their effects on metallic bonds
- regions of a solid substance with a regular arrangement of particles
- properties of solid depend on the density and size of the crystals
- small crystals = harder (less movement between layers of cations) and more brittle (more disruptions between the crystals within the solid)
- the arrangement and size of crystals can be changed by work hardening and heat treatment respectively
describe the process of work hardening
- hitting metal until it is flattened out which pushes the layers of crystals together - strengthens and hardens the material
- strengthens it through plastic deformation which is the process by which a metal is permanently changed in shape/form by a strong force
describe the processes of heat treatment
- change the physical properties of a metal by changing the size of the crystals
- heat up the metal joins all the crystals and then cooling it at different speeds to reform the crystals - faster you cool it down the smaller the crystals will be
- annealing - metal heated and then cooled slowly (large crystals so softer and increased ductility
- tempering - metal cooler relatively slowly so relatively large crystals are formed which are harder and less brittle
- quenching - metal cooled very fast sometimes by plunging in to water causing a very hard but brittle metal to be produced
describe coatings
- can have decorative or functional purpose
- surface coating creates a physical boundary between teh metal and outside world (paint and powder coating)
- > powder coating is when a bunch of finely grounded charged particles are sprayed on a surface and then when the are heated they fuse and create a layer that is resistent to marking and scratiches
- can also have chemical coatings which create a chemical protection from rusting
- > eg. galvanised steel is when there is a layer of zinc oxide on teh steel which reacts with carbon and oxygen in teh air to slow down rusting
describe each type of metal and its properties
1) alkali
- most reactive and very soft
- low melting points
- low core charge, low ionisation energy and large atomic radius
2) alkali earth
- less reactive then alkali but still reactive
- commonly found in minerals - rarely found pure
- harder then alkali
- higher melting points then alkali
3) transition
- usually silver and most look the same
- less reactive then alkali/earth (some chemically inert - noble metals = gold, platinum, silver etc)
- they are shiny, malleable, ductile (used for industrial purposes), high melting points, hard and high tensile strength (can be stretched alot)
- high density as atoms are very small (high core charge)
4) poor/post-transition metals
- usually relatively soft and have low melting/boiling points
what is iron ore and what are the three main forms
- iron ore is usually iron oxide and rock stuff
- hematite Fe203 - dark, shiny, turn red when exposed to oxygen red dirt
- pyrite FeS2 - fools gold, used to get sulphur too
- magnetite Fe304 - used for early compasses, black mineral
how do you get the iron out of an iron ore
blast furnace
