COVALENT BONDING- diamond & graphite

Question 1

in what forms can carbon exist

Answer 1

diamond
graphite
graphene
Buckminster Fullerene (bucky balls)

Question 2

whats an ALLOTROPE

Answer 2

elements that can exist in different forms but stay in the same state
(like the different forms of carbon)

Question 3

bonds (of carbon) and structure

in DIAMOND

Answer 3

-4 bonds
(1 atom, 4 bonds)
-are all STRONG COVALENT
-because all the carbon atoms are joined to lots of others
-it takes ENORMOUS AMOUNTS OF ENERGY to break the bonds
-very high melting points ( =sublimation at 3500*c )
- has a TETRAHEDRAL STRUCTURE

Question 4

diamond strength=
when pressure is applied to the structure of a diamond, its …
throughout the lattice.
this allows it to be extremely strong, but its also…

This property means the INDUSTRIAL USE OF DIAMOND IS…

Answer 4

• evenly dispersed/ spread out/ equally distributed
• brittle
• cutting and grinding

Question 5

bonds (of carbon) in GRAPHITE

Answer 5

-3 bonds
(1 atom, 3 bonds)
- are all STRONG COVALENT BONDS
-because all the carbon atoms are joined to lots of others
-it takes ENORMOUS AMOUNTS OF ENERGY to break the bonds
-very high (sublimation) melting points

Question 6

structure of GRAPHITE

Answer 6

-hexagonally planar in shape (flat hexagons)
-each layer of molecules is held together by WEAK INTERMOLECULAR FORCES
(like a stack of books held together by magnets)
-this force allows the LAYERS OF CARBON TO SLIDE OVER EACH OTHER
(you cannot just pull them straight apart, have to slide like VELCRO)

Question 7

the sliding property allows GRAPHITE to be used industrially as a …

Answer 7

solid lubricant

Question 8

conducting electricity

Answer 8

• to be able to conduct electricity a substance must have CHARGED PARTICLES (ions or electrons)
• that are able to MOVE UNDER THE INFLUENCE OF A POTENTIAL DIFFERENCE

Question 9

DIAMOND conductivity

Answer 9

-cannot conduct electricity because there are no charged particles
(but is covalently bonded)

Question 10

GRAPHITE conductivity

Answer 10

• each carbon in graphite has 4 OUTER SHELL ELECTRONS
• it only uses 3 to form the covalent bonds
• the 4th is placed in an area between the layers
• this electron is NEGATIVELY CHARGED and can MOVE around the layers
• but it wont move unless THERE’S A POTENTIAL DIFFERENCE
• GRAPHITE IS ABLE TO CONDUCT ELECTRICITY.

Question 11

in between the layers of GRAPHITE, there is a …

Answer 11

SEA OF DELOCALISED ELECTRONS

the 4th electron on the outer shell that isnt used in graphite