Giant covalent structures

Question 1

what is a giant covalent structure

Answer 1

structures with a lattice (network) of covalent bonds which repeats throughout the whole structure

Question 2

properties of diamond

Answer 2

each carbon atom forms four covalent bonds with other carbon atoms. this network of strong bonds extends unbroken throughout the entire structure. diamond does not conduct electricity as it has no delocalised electrons. High melting point and is very hard.

can be used for the tip of a drill or for jewellery

Question 3

properties of graphite

Answer 3

in graphite, carbon atoms are hexagonally arranged in layers. Graphite is soft and can be easily scratched. The layers can slide over one another so can be used in pencils or can be used as lubricant. can conduct electricity as it has one delocalised electron so when voltage is applied the delocalised electrons can move along the layers. three of the electron atoms are covalent bonds

Question 4

silicon dioxide

Answer 4

each silicon dioxide atoms is bonded to 4 oxygen atoms. Each oxygen atom is bonded to two silicon atoms. The arrangements of the units is in the shape of a tetrahedron. similar properties to diamond.

very hard as it has a high melting point because of the strong covalent bonding throughout the structure.

Question 5

metallic bonding

Answer 5

metal atoms in a lattice tnd to lose their outer electrons and become positive ions.
the electrons that are lost are free to move throughout the lattice. they form a ‘sea’ of delocalised electrons.
a metallic bond is formed by the attractive forces between the delocalised electrons and the positive ions.

Question 6

what is metallic bonding

Answer 6

a lattice of metal ions surrounded by a ‘sea’ of delocalised electrons.

Question 7

why does metal conduct electricity whether solid or molten

Answer 7

this is because the delocalised electrons can move between the ions in the metal lattice when a voltage is applied.

Question 8

what happens when a force is applied to a metal

Answer 8

the layers slide over one another. when the pushing or pulling is no longer present, new attractive forces can be formed between the delocalised electrons and the metal ions so the properties stay the same