C3 - Bonding Flashcards
An ionic bond occurs between what atoms?
A metal and a non-metal atom
A covalent bond occurs between what atoms?
2 non-metal atoms
A metallic bond occurs between what atoms?
2 metal atoms
In ionic bonds what are the 2 atoms attracted by?
Electrostatic force
Ionic compounds exist in what structure and why?
Lattices
It forms because each ion is electrostatically attracted in all directions to ions of the opposite charge.
In covalent bonds what are the 2 atoms attracted by?
Electrostatic force
What is a dative/co-ordinate bond?
A dative covalent bond is a covalent bond in which a shared pair of electrons has been supplied by one of the bonding atoms only.
How is a dative bond shown in a dot and cross diagram?
By → or ← with the arrow coming from the atom that provided the electrons
In metallic bonds what are the 2 atoms attracted by?
Electrostatic force between the metal ions and the electrons
How does metal ion size affect the strength of metallic bonds?
The smaller the metal ion, the closer the positive nucleus is to the delocalized electrons. This means there is a greater attraction between the two, which creates a stronger metallic bond.
Do ionic structures conduct electricty?
They conduct electricity when molten or dissolved in water as the ions are free to move
Do metallic structures conduct electricty?
They conduct electricity when solid or molten due to movement of delocalised electrons
Do marcomolecular structures conduct electricty?
They do not apart from graphite in a solid
Do molecular structures conduct electricty?
Does not conduct electricty as there are no charged particles
What is the boiling and melting point of ionic structures?
High as breaking strong ionic bonds requires lots of energy
What is the boiling and melting point of metallic structures?
High as breaking electrostatic forces of attraction requires lots of energy
What is the boiling and melting point of macromolecular structures?
Very high as they have many strong covalent bonds
What are the properties of ionic structures?
Hard due to strong electrostatic forces of attraction that hold ions together
What is the boiling and melting point of molecular structures?
Low as they are small structures with weak bonds
What is a molecular structure?
Simple covalent
What are the properties of metallic structures?
Malleable and Ductile as layers slide over each other
What are the properties of macromolecular structures?
Varies depending on the structure
E.g. rigid and hard for diamond but brittle for graphite
What are the properties of molecular structures?
Brittle as they don’t have strong bonds holding them together