covalent bonding (4.2) Flashcards
what happens when non metal atoms bond
they share a pair of electrons to get a full outer shell (covalently bond)
covalent bond definition
the electrostatic force of attraction between protons in 2 nuclei and a shared pair of electron between them
what does the shared per of electrons do
pull the nuclei of the atoms closer together
is a covalent bond a strong or weak attraction
very strong
what is a small group of atom held together by a covalent bond called
a simple molecule
what is an example of a simple molecular substance
C60 fullerine
properties of a simple molecular substance
low boiling points
weak intermolecular forces
strong covalent bonds
don’t conduct electricity
why do simple molecular molecules have low boiling points
due to their weak intermolecular forces
when simple molecular substances boil, the weak intermolecular forces break
why can’t simple molecular substances conduct electricity
its molecules are neutral
what is C60 fullerine
a simple molecular substance made of 60 carbon atoms in a ball
c60 fullerine properties
-low boiling point, but not as low as other molecules due to its high molecular mass
-soft and slippery because the molecules can roll over each other easily
-electrical insulator because the molecules are neutral
what is a giant covalent substance
a solid with a very high melting point, with atoms that are linked by strong covalent bonds
examples of giant covalent substances
diamond
graphite
silicone dioxide
what is diamond
a giant covalent structure, which is a form of pure carbon arranged into a giant lattice
structure of diamond
-every carbon atom makes 4 covalent bonds
-tetrahedral shape
-strong, grid-like arrangement
properties of diamond
-sublimes at a very high temperature due to strong covalent bonds, lots of bonds in the giant lattice, and lots of energy is required to break all the bonds
-one of the hardest substances, so used in cutting
-cannot conduct electricity because there is no freely-moving charged particles
-all the atoms are neutral
-all the electrons are stuck inside an atom or a bond
what is graphite
a giant covalent structure, which is a form of pure carbon arranged into a giant lattice
structure of graphite
-layers of hexagonal carbon stoms
-every carbon makes 3 covalent bonds
-weak intermolecular forces between layers
-delocalised electrons inside each layers
properties of graphite
-sublimes at a very high temperature due to strong covalent bonds, lots of bonds in the giant lattice, and lots of energy is required to break all the bonds
-soft and slippery bc the layers can slide easily, so its used as a solid lubricant
-conducts electricity due to delocalised electrons can move freely
what is silicon dioxide
a giant covalent structure which is known as silica
structure of silicon dioxide (silica)
-every silicon atom makes 4 covalent bonds
-every oxygen atom makes 2 covalent bonds
-tetrahedral shape (like diamond)
-strong, grid like arrangement
properties of silica
similar properties to diamond due to its similar bonding and structure
however its much less expensive because its much less rare.
