topic 2 Flashcards
Metallic bonding properties
High MP/BP
malleable
good thermal/electrical conductors
high densities
Ionic bonding properties
High MP/BP
Only conduct when molten or dissolved
crystalline structures
water soluble
Covalent bonding properties
Low MP/BP
low enthalpies of fusion and vaporisation
poor electrical and thermal conductors
Form simple and giant molecules
Why do polar bonds happen
If one atom nucleus attracts more strongly than the other nucleus
how are polar bonds formed and what are they represented by
One end of the bond has a slight excess of negative charge and is represented by 𝛿-
On the other side of the bond is more positively charged and is represented by 𝛿+
What is electronegativity
It is the ability for an atom to gain an electron
What is the trend of electronegativity
Bottom right is the lowest and top right is the highest
What are the properties if the bond is more polar
If the bond is more polar then it is possible for it to have ionic properties
How does a compound become completely ionic
When the difference in electronegativity is large enough to remove electrons from the other elements
What are polar molecules
They are little electrical dipoles
What do polar molecules look like
One end has a positive electrical pole and the other side has a negative electrical pole
What are dipoles
The two opposite charges in a polar molecule are dipoles
What is the dipole moment
The bigger the dipole the the bigger the twisting effect
What does the electronegativity difference have to be to become polar or not
If greater than 0.5 electronegativity then polar
if less than 0.5 electronegativity then non-polar
Diamond properties
Strong covalent bonds with 4 bonds on each carbon atom
Tetrahedron shape
High MP/BP
does not conduct electricity due to no free electrons
