Bonding Flashcards
Types of chemical bonds?
Ionic
Covalent
Dative/co-ordinate covalent
Metallic
Types of physical bonds?
Van der Waals’ forces
Dipole-dipole interaction
Hydrogen bonds
What is an ionic bond?
An electrostatic force of attraction between positive and negative ions, usually between a metal and a non-metal
Structure of ionic compounds?
Each ion attracts oppositely charged ions in all directions. Resulting in a giant ionic lattice structure containing billions of atoms
Properties of ionic bonds in regards to melting/boiling?
Most are solids at room temperature as there is insufficient energy to overcome the strong electrostatic forces of attraction so most have high melting and boiling points
the greater the ionic charge the higher the point
The larger the ion the lower the point as weaker bonds due to being spread over a large surface
Properties of ionic bonds in regards to solubility?
Most soluble in polar solvents such as water. Ionic lattice is broken down and solvent molecules surround the ions. The stronger the lattice the less soluble to compound.
Properties of ionic bonds in regards to electrical conductivity?
Can conduct electricity it only if charged ions can move. So solids cannot but molten/ dissolved compounds can.
What is a covalent bond?
Strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms. Occurs in non metals elements, non metal compounds and poly atomic ions
What is a simple covalent molecule?
A few atoms held together by covalent bonds
What are giant covalent structures?
Contain many atoms, each joined to adjacent atoms by covalent bonds. Usually arranged into giant regular lattices
Properties of simple covalent structure in regards to temperature?
Low melting and boiling points as less energy needed to break weak intermolecular forces (not strong covalent bond)
Properties of simple covalent structure in regards to solubility?
They can either be polar or non-polar.
Polar molecules dissolve in polar solvents.
Non-polar molecules dissolve in non-polar solvents
Properties of simple covalent structure in regards to electrical conductivity?
Do not conduct electricity as they do not have any free electrons or an overall electric charge
What is an allotrope?
A different form of the same element in the same state. E.g. graphite and diamond
Properties of giant covalent structure in regards to temperature?
High melting and boiling points due to presence of strong covalent bonds in the structures
Properties of giant covalent structure in regards to electrical conductivity?
Depends if there are any delocalised electrons. E.g. graphite will conduct but diamond will not
Properties of giant covalent structure in regards to solubility?
They are not soluble as covalent bonds in the lattices are too strong to be broken
What is metallic bonding?
Electrostatic interaction between positive metal ions and delocalised electrons. The atoms are ionised and these ions occupy fixed positions in the lattice. Outer shell electrons are delocalised and shared between all atoms within the structure
Properties of metallic bonds in regards to electrical conductivity?
Most conduct electricity in solid and liquid state. The delocalised electrons can move through the structure carrying a charge
Properties of metallic bonding in regards to temperature?
Most metals have high melting and boiling points. Depends upon the strength of metallic bonds within the structure. High temperatures are needed to overcome strong electrostatic attraction between the cations and electrons. The higher the ionic charge of the metal the higher the melting point
Properties of metallic bonds in regards to solubility?
Metals do not dissolve. Any interaction between polar solvents and changed in metallic lattice would lead to reaction rather than dissolving
Properties of metallic bonds in regards to malleability/ductile?
Metals can be hammered and pressed into shape as atoms can roll over each other into new positions without the bonds breaking
Metals can be drawn out into a wire again due to atoms rolling over each other
What is an alloy?
Mixtures containing metals. Not a compound as there can be different ratios of metals. They can modify a metals properties e.g. ions may be different sizes to stop layers moving past each other making it harder
What is a dative/coordinate bond?
Very similar to a covalent bond apart from both electrons involved in the bond are from the same atom.