chemistry metallic bonding

what it called when metals bond with other metals

metallic bonding

definition of an element

collection of the same atoms

properties of metals

Malleable, Ductile and Good Conductors of Heat and Electricity

metals become ions with a what charge?

positive

why are electrons delocalised

positive ions lose electrons the electrons are then spread out across all the ions in the structure.

definition of an alloy

A mixture of two or more different metals.

definition of metallic bonding

strong electrostatic force of attraction between a regular structure of positive ions and delocalised electrons.

why do alloys have higher strenghth than pure metals

atoms of different elements are different sizes this distrupts the regular layered structure the layers can no longer slide over each other.

example of alloys

steel, brass, bronze

what are transition metals

The elements (all of which are metals) that are positioned in the large central block of the periodic table between Group 2 and Group 3.

What is sacraficial protection?

The process to prevent corrosion, where iron is connect to a more reactive metal (e.g. zinc or magnesium). The more reactive metal corrodes in preference to the iron.

what is galvanising

The process of 'Sacrificial Protection' where zinc is the more reactive metal.

what is electroplating

The process of coating a metal object with a thin layer of another metal, using electricity. This can be to prevent corrosion (e.g. a tin can), or to make it look more attractive.

what is corrosion

The destruction of materials by chemical reactions with substances in the environment. Rusting is an example of corrosion - both air and water are necessary for rusting to occur.

what is the only metal that can't rust

Iron

what do transition metals form.

Coloured compounds

what do alkalis form

colourless compounds

properties of transition metals

high melting point, not reactive, ionic compounds with non metals, good conductors of thermal and electrical energy, high density

what bronze made out of

tin + copper

ways of extracting metal

bioleaching, electrolysis, phytomining, displacment

describe bioleaching

uses bacteria to produce leachate solutions that contain metal compounds. purify it with electrolysis.

describe electrolysis

Electrolysis is a process in which electrical energy, from a direct current (dc) supply, breaks down electrolytes. The free moving ions in electrolytes are attracted to the oppositely charged electrodes which connect to the dc supply.

describe phytomining

Growing plants on contaminated land to extract the metals. the plants are then burnt and the metal extracted from the ash.

describe displacment

more reactive metal displaces a less reactive metal.

advantages of recycling

less fossil fuels, cheaper, less co2, serves limited resources

disadvantages of recycling

describe smelting

The process by which ore is melted to separate the useful metal from other elements.

what is an ore

rock containing metal compounds. metal ores are rocks containing enough metal compound to make extraction economically viable.

why doesn't aluminium corrode

It forms a protective layer of aluminium oxide that stops oxygen from coming into contact with the metal