Covalent Bonding Flashcards

1
Q

definition of covalent bonding

A
  • atoms form covalent bonds by sharing pairs of electrons, meaning they both have full outer shells.
  • strong electrostatic attraction between negative shared electrons and positive nuclei of atoms involved
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2
Q

simple molecular substances

A
  • atoms within a molecule are held together by very strong covalent bonds
  • the forces of attraction between the molecules are very weak
  • this means melting and boiling points are very low because the molecules are easily separated
  • mostly gases or liquids at room temp
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3
Q

Giant covalent structures

A
  • all the atoms are bonded to each other by STRONG COVALENT BONDS
  • there are lots of bonds which means it takes a lot of energy to break them, so giant covalent structures are SOLIDS with VERY HIGH MELTING AND BOILING POINTS
  • DONT conduct electricity (except graphite)
  • insoluble in water
  • eg diamond and graphite
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4
Q

diamond

A
  • carbon atoms with 4 covalent bonds
  • high melting point = hard to break covalent bonds
  • rigid lattice structure = very hard
  • doesn’t conduct electricity as no free electrons or ions
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5
Q

graphite

A
  • each carbon atom only forms 3 covalent bonds, creating layers of carbon atoms. the layers are only held together weakly by intermolecular forces so are free to slide over each other = soft and slippery
  • high melting point = strong bonds within the layers
  • conducts electricity = one delocalised electrons that can conduct electricity
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6
Q

C60 fullerene

A
  • hollow spheres of 60 carbon atoms
  • not a giant covalent structure just made up of large covalent molecules
  • only held together by intermolecular forces so can slide over each other = soft
  • does have a delocalised electron but it cannot move between molecules so it’s a poor conductor of electricity
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