- Covalent bonding happens when a non-metal bonds with a metal.
- Formed when a pair of electrons are shared between two atoms which hold the two electrons together.
- When the electrons are shared, the outer shells overlap and both atoms now have a full outer shell.
SIMPLE MOLECULAR COVALENT SUBSTANCES
This refers to almost all covalent compounds and molecules.
They are 'simple' because each molecule contains a relatively small, fixed number of bonds.
- eg: Water (H20) and Glucose (C6 H12 06)
- LOW melting and boiling points.
even though the bonds between the atoms are VERY STRONG, the bonds between the molecules are VERY WEAK.
so a small amount of energy is needed to break the molecules.
GIANT COVALENT COMPOUNDS- Diamond.
- Every carbon atom is bonded to 4 other carbon atoms in a very ordered way.
- The strongest substance known to man due to all the strong covalent bonds.
- Diamond cannot conduct electrcity because all the electrons are fixed in covalent bonds.
GIANT COVALENT COMPOUNDS- Graphite.
- Made from carbon (like diamond)
- Every carbon atom has one electron NOT involved in bonding in its outer shell.
- This means these electrons become delocalized over the surface of the sheet.
- Means graphite can conduct electricity.
- High melting and boiling point (strong covalent bonds within layers need a lot of energy to be broken)
SEPARATING IMMISCIBLE LIQUIDS
Immiscible liquids: Liquids that don't dissolve in eachother.
~separating immiscible liquids~
-separating liquids like OIL AND WATER can be easily done with a separating funnel.
- let 2 liquids settle on top of eachother. the denser liquid will settle at the bottom.
- so the bottom liquid will come out of the funnel first when you open the tap.
- when the bottom liquid has come out, quickly shut the tap before the second one does.
SEPARATING MISCIBLE LIQUIDS
We cannot use a separating funnel to separate miscible liquids as they dissolve into eachother when shaken.
We have to use FRACTIONAL DISTILLATION:
-separates substances by their boiling points.