C2 - Bonding, Structure and Properties of Matter Flashcards
Define Covalent bond
A shared pair of electrons between two non-metals
Properties of a diamond.
4 covalent bonds for each carbon atom
High melting point
Hard (strong bonds)
Does not conduct (no delocalised electrons)
What are Electrostatic forces?
The strong forces of attraction between oppositely charged ions.
What is Graphene?
A single layer of graphite
Define Gas?
The state of matter where the particles have the most energy. The particles in a gas are relatively spread out and move randomly in all directions.
What are polymers?
Large molecules made by linking together large numbers of smaller molecules called monomers.
Nanoparticles
Nanoparticles have diameters between 1 nm to 100 nm in size.
Properties of Graphite.
A giant covalent structure which is made up of carbon atoms
each of which form three covalent bonds with three other carbon atoms.
This forms layers of hexagonal rings held together by weak inter molecular forces which means that layers are free to slide and can be used as a lubricant.
High melting point due to strong covalent bonds.
Conduct thermal and electricity due to one delocalised electron per carbon atom.
Ion
An atom or molecule with an electric charge due to the loss or gain of electrons.
Ionic compound
Giant structure of ions, held together by strong electrostatic forces.
What are intermolecular forces?
The forces which exist between molecules. The strength of the intermolecular forces in covalent bonds impact physical properties like boiling/melting point.
What is a lattice?
A repeating regular arrangement of atoms/ions/molecules. This arrangement occurs in crystal structures.
What is Ionic bonding?
Electrostatic attraction between positive and negative ions.
How are ionic compounds held together?
Held together in a giant lattice. Strong electrostatic attractions holds the structure together.
State the properties of ionic substances.
High melting point and boiling point.
Do not conduct electricity when solid.
Conduct when molten or dissolved in water - ions are free to move.
How are ionic compounds formed? In the MgO case.
Reaction with a metal with a non-metal.
Magnesium is in group 2 so can give away 2 electrons.
Oxygen is in group 6 so can gain two electrons to get a full outer shell.
Mg becomes Mg 2+. O become O 2-.
What is a covalent bond?
The electrostatic attraction between a shared pair of electrons and the nuclei of the atoms, between two non-metals.
Properties of molecular covalent substances.
Doesn’t conduct - no ions.
Low melting point and boiling points because of the weak inter-molecular forces between molecules.
How do inter molecular forces change as the mass/size of the molecule increase?
Inter molecular forces increase as well.