simple molecules and covalent bonds; giant covalent structures; metallic bonding

covalent bond

when a pair of electrons are shared between two atoms

covalent bond properties

• low melting/boiling point

• cannot conduct electricity in molten,aqueous, and solid state (it is a stable atom, there are no ions which results in no mobile ions to carry charge)

graphite

• used as a lubricant (the layers slide over each other due to weak intermolecular forces)

• used as an electrode because it has mobile electrons

• contains strong covalent bonds between carbon atoms

• each carbon atom is bonded covalently to three other atoms

• made of pure carbon

diamond

• made of pure carbon

• used for cutting tools or jewellery

• each carbon atom is bonded covalently to four other atoms

• it is really hard due to the strong covalent bodns

• cannot conduct electricity (no delocalised electrons)

• high melting/boiling points

• similar to silicon (IV) oxide

metallic bonding

the electrostatic attraction between the positive ions in a giant metallic lattice and a ‘sea’ of delocalised electrons

metallic bond properties

• good conductors of electricity (delocalised electrons)

• malleable/ductile

• shiny

• high melting/boiling points

• usually dense as the particles are close together

• strong

delocalised electrons

• free moving electrons contributing to electrical conductivity by carring charge

• allows metal atoms to slide past one another, allowing it to be malleable/ductile