4.1 Covalent Bonding Flashcards
Define covalent bonding
electrostatic attraction between two positively charge nuclei and a shared pair of electrons
What is a simple molecule?
small group of atoms held together by covalent bonds
What does the shared pair of electrons do?
pull the nuclei of atoms closer together
Covalent bonding is very…
strong
Why does simple molecular substances have low boiling points?
the weak intermolecular forces break but not bonds
Intermolecular forces are very…
weak
Where do intermolecular forces act?
in between the molecules
Where do the covalent bonds act?
in the molecules , making the molecules
Why does molecular mass increase with boiling point?
strength of intermolecular forces increases
more energy needed
Can simple molecular molecules conduct electricity?
cannot conduct because a charge is needed
What is C60 fullerene?
simple molecule made of 60 carbon atoms
Why does C60 fullerene have a low boiling point?
simple molecule
-> weak intermolecular forces
-> not much energy needed
C60 fullerene has a….
low boiling point
What are the properties of C60 fullerene?
soft and slippery
electrical insulator
Why is C60 fullerene soft and slippery?
molecules can roll over each other
Why is C60 fullerene an electrical insulator?
molecules are neutral NOT charged
What is diamond?
form of pure carbon arranged into giant lattice
What structure does diamond have?
giant lattice
every Carbon has 4 covalent bonds so no free bonds
tetrahedral shape
strong
grid like shape
How many covalent bonds does each carbon have in diamond?
4
none free
What shape is diamond?
tetrahedral
Why does diamond sublime at every temperature?
covalent bonds are strong
lots of bonds in giant lattice
lots of energy needed to break
Why is diamond used for cutting?
it is very hard
What is diamond used for?
cutting glass
Why cannot diamond
conduct electricity?
no freely moving particles
all atoms neutral
all electrons in atom or bond
What is graphite?
pure carbon arranged into a giant lattice
What is the structure of graphite?
layers of hexagons of Carbon atoms
every carbon has 3 covalent bonds
weak intermolecular forces
delocalised electrons inside each layer
Why does graphite sublime at a high temperature?
covalent bonds are strong
lots of bonds in giant lattice
lots of energy needed to break
What are the properties of graphite?
soft and slippery
conducts electricity
What is graphite used for?
solid lubricant
Why is graphite used as a solid lubricant?
soft and slippery
Why can graphite conduct electrcity?
delocalised electrons can move freely
What is silicon dioxide?
giant covalent substance made of silicon and oxygen
What is another name for silicon dioxide?
silica
What is the structure of silicon dioxide?
every silicon has 4 covalent bonds
every oxygen has 2 covalent bonds
tetrahedral shape
strong
grid-like arrangement
Why does silicon dioxide sublime at high temperatures?
covalent bonds are strong
lots of bonds in giant lattice
lots of energy needed to break
What elements does covalent bonding occur between?
non metal + non metal
Are covalent bonds insulators or conductors?
insulators
Why is Graphite so soft?
layers of hexagons can slide
Why is Diamond so hard?
lots of covalent bonds
