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Flashcards in topic 7 types of substance Deck (15):

what are the properties of covalent substance?

low melting points

not soluble in water

poor conductors of electricity


why do covalent compounds have low melting points

there are only strong forces holding the atom in the molecules, and very weak bonds hllding the molecules to one another


why are covalent substance poor conductors?

the electrons cannot properly ove around the atoms as the are held in place , attched to tother atoms 


what is the stucture of a polymer?

a polymer is like a large molecule consisting of a repeating patter of monomers(simple molecules)which are molecularly bonded to each other in a long chain where by the carbon atoms are covalently bonded to each other


what are 3 common allotropes of carbon

diamond, buckminster fullerenes, graphite


what are the main difference between covalent, simple molecules and giant covalent structures


  1. a lot bigger
  2. very high melting points
  3. some can conduct electricity
  4. some form very large molecules(e.g. fullerenes), some can be infinitly large(e.g. nano tubes)


what is the structure and properties of diamond

diamond is an allotrope of carbon, in which each carbon atom is covalently bonded to 4 other carbon atoms.

it has a high melting point, doesnt conduct electricity, transparent and very hard 


what is the structure and properties of fullerenes

fullerenes are giant molecules consisting of 28, 32, 50, 60, 70, 240 etc, carbon atoms, in a spherical shape with man sides in the shape of a regular pentagon or hexagon.

forms a black solid which is soluble in various solvents, cant conduct eectricity on its own, has delocated electrons which move around but are confined to each molecule


what is the structure and properties of graphite

consists of layers of sheets of carbond arranged in hexagons, with each carbon atom bonded to 3 others, each atom has a delocalised electron which moves freely around its layer.

high melting point, insoluble in water, conducts electricity because the delocalised electrons can carry charge acros the substance



what is the structure and properties of graphene

arranged i9n a single layer sheet of carbon atoms bonded to 3 others, in a regular hexagon shape, each atom has a delocalised electron

it has a high melting point and is very strong, conducts electricity well because of its delocalised electrons


what is the structure of metals

metal ions are arranged in a regular patter within a sea of delocalised electrons, which these positively charged metal ion are attracted to


why are metals malleable

due to the regular arrangement of atoms, layers are able to slide over each other to move out of the way and easily change shape instead of shattering  


why do metals conduct electrons

the sea of delocalised electrons are able to move freely around the metal ions and can carry charge throuh the substance


what are the typical properties of metals


high melting point

good conductor of heat and electricity

high density



what are the typical properties of non-metals


low melting points

poor conductors of electricity and heat

low density