covalent bonding 4.2 Flashcards
what’s covalent bonding dot cross diagrams?
when non-metal atoms bond, they share pairs of electrons to get a full outer shell
what is the definition of covalent bonding?
covalent bonding is the electrostatic attraction between protons in two nuclei and a shared pair of electrons between them
what’s type of attraction is covalent bonding?
very strong attraction
what is a simple molecule?
a small group of atoms held together by covalent bonds
why do simple molecular substances of covalent bonds have low boiling points?
simple molecules contain very strong covent bonds but also weak intermolecular forces between the molecules
when simple molecular substances boil it’s the weak IMFs which break
what’s the relation between simple molecular substances and molecular mass?
as molecular mass increases, so does the strength of the weak IMFs
increasing the boiling point
do simple molecular substances conduct electricity?
no
as they don’t have charged particles that can move freely
molecules are neutral
what’s an example of a simple molecular substance?
C60 fullerene
composed of sixty carbon atoms
low boiling point, but not as low as others as it has a high molecular mass
soft and slippery solid as molecules can roll over each other
electrical insulator as the molecules are neutral
what is diamond - covalent bonding?
a pure carbon
arranged into a giant lattice
every carbon makes 4 covalent bonds
tetrahedral shape
strong
sublimes at a very high temperature
why does diamond and silicon sublime at a very high temperature?
covalent bonds are very strong
lots of bonds in the giant lattice
lots of energy required to break all the bonds
what is one of the uses of diamond?
cutting
as it is a hard substance
can the giant lattice of diamond and silicon conduct electricity?
it cannot conduct electricity as there are no moving particles
all the atoms are neutral and the electrons are stuck inside a bond
what is graphite - covalent bonding?
pure carbon
giant lattice
layers of hexagons of carbon atoms
every carbon makes 3 covalent bonds
weak intermolecular forces between layers
delocalised electrons inside each layer
soft and slippery as layers can slide easy, used as a solid lubricant
why does graphite sublime at a high temperature?
- covalent bonds are strong
- lots of bonds in the giant lattice
- lots of energy is needed to break the bonds
can graphite conduct electricity?
yes as the delocalised electrons can move freely inside the layers
