4.1 - Covalent bonding Flashcards
what happens when non-metal atoms bond
they share pairs of electrons to get a full outer-shell
how many times does N always share
3 times
how many times does O always share
2 times
what molecules contain double pairs
oxygen
carbon dioxide
what molecule contains a triple pair
nitrogen
what is covalent bonding
the electrostatic attraction between protons in two nuclei and a shared pair of electrons between them
what do the shared pair of electrons do to the nuclei of atoms in covalent bonding
pull the nuclei of the atoms together
what type of attraction is covalent bonding
very strong attraction
what is a simple molecule
a small group of atoms held together by covalent bonds
what are between the molecules in simple molecules
although they contain very strong covalent bonds there are weak intermolecular forces between the molecules
when they boil the weak IMFs break
what happens to the strengths of the weak IMFs as molecular mass increases
the strength also increases which results in the boiling point increasing
what does electrical conductivity require
charged particles that can move freely
are there charged particles in a simple molecular substances
no
do simple molecular substances conduct electricity
no never because molecules are neutral
what is C60 fullerene
a unique simple molecule of sixty carbon atoms in a ball
why is the boiling point of C60 fullerene low but not as low as other molecules
because of its high molecular mass
why is C60 fullerene a soft and slippery solid
the molecules can roll over each other easily
why is C60 an electrical insulator
the molecules are neutral
what is diamond
a form of pure carbon arranged into a giant lattice in which every C makes 4 covalent bonds, tetrahedral shape and has a strong gird-like arrangement
why does diamond sublime at a very high temperature
covalent bonds are very strong
there are lots of bonds in the giant lattice
lots of energy is required to break all the bonds
what is diamond used for
cutting because it is one of the hardest substances
why is diamond one of the hardest substances
covalent bonds are very strong
there are lots of bonds in the giant lattice
lots of energy is required to break all the bonds
can diamond conduct electricity
no because there are no freely-moving charged particles - all the atoms are neutral and all the electrons are stuck inside an atom or bond
what is graphite
a form of pure carbon arranged into a different giant lattice - in which
there are layers of hexagons of C atoms
every C makes 3 covalent bonds
weak intermolecular forces between layers
delocalized electrons inside each layer
why does graphite sublime at a very high temperature
covalent bonds are very strong
there are lots of bonds in the giant lattice
lots of energy is required to break all the bonds
what is graphite used for
as a solid lubricant because it is soft and slippery so the layers can slide easily
can graphite conduct electricity
yes because inside the layers the delocalized electrons can move freely
what is silicon dioxide
also known as silica - it has a giant covalent structure
every Si makes 4 covalent bonds
every O makes 2 covalent bonds
tetrahedral shape like diamond
strong, grid-like arrangement
why is silicon dioxide less expensive than diamond
it is much less rare
why does silicon dioxide sublime at a very high temperature
covalent bonds are very strong
there are lots of bonds in the giant lattice
lots of energy is required to break all the bonds
can silicon dioxide conduct electricity
no because there are no freely-moving charged particles - all the atoms are neutral and all the electrons are stuck inside an atom or bond
what bonding does a metal and non-metal have
ionic
what structure does ionic bonding have
giant lattice
what are the essential properties of ionic bonding
high MP/BP
insulator when solid
conductor when liquid
conductor when aq
other properties of ionic bonding
brittle
usually soluble in water
crystalline
what bonding do only non-metals have
covalent
what is the structure of covalent bonding
simple molecules
what are the essential properties of covalent bonding - simple molecules
low MP/BP
insulator
what are other properties of simple molecules with covalent bonding
usually insoluble in water
dull
what type of bonding do only metals have
metallic bonding
what structure does metallic bonding have
giant lattice
what are the essential properties of metallic bonding
high MP/BP
conductor
what are other properties of metallic bonding
malleable
ductile
shiny
