Ionic Bonding- Metal and Non-Metal Ions
Ionic bonding is the transfer of electrons, forming ions, to give full
valences. Metals lose electrons to become positive ions and non-
metals gain electrons to become negative ions. The opposite
charges attract, forming strong forces of electrostatic attraction.
Ionic substances form lattices with strong forces of electrostatic
attraction between each ion and all its surrounding, oppositely-
Properties of Ionic Compounds
• When molten or aqueous, they conduct electricity. This is due to
the ions being free and mobile. Therefore, they are able to carry
charge through the fluid.
• They have high melting and boiling points as they have strong
electrostatic forces of attraction inside the lattice. Therefore, a
large amount of energy is required to overcome these forces,
which is only met at a high temperature. They are always solid at
• They are brittle and will shatter easily, as a heavy blow to the
lattice may cause same-charged ions to come into contact and
Covalent Bonding- Multiple Non-Metals
Covalent bonding is the sharing of electrons between atoms, to give
full outer shells. In a bond, electrons may sometimes be attracted
to one atom more than the other, due to a significantly higher
nuclear charge and electronegativity, forming partial negative (δ-)
and partial positive (δ+) charges in a polar bond. The electrons in
the bond are in pairs, and each atom now has a noble gas
arrangement. Macromolecules are much larger covalent compounds
and have vastly different properties to simple molecular
Properties of Molecular Covalent Compounds
• They have a very low melting and boiling point due to the fact
they have very weak intermolecular van der Waals forces. Many
are gases at room temperature. Water, however, has hydrogen
bonding and is thus a liquid between 0 and 100˚C.
• They are very poor conductors, even when aqueous or molten
because they have neutral charges and so they cannot carry a
Properties of Macromolecular Covalent
• They have very high melting and boiling points as they have very
strong intramolecular covalent bonds which require large amounts
of energy to be overcome. However, they have very weak
• Graphite, only, will conduct as it has electrons between its layers
that can carry current.
Dative Covalent Bonds
Dative covalent bonds are formed when both electrons in a bonding
pair are donated by one of the atoms, only. In a dative covalent
bond, the atom that does not provide electrons doesn’t have a filled
outer shell of electrons and is electron deficient. The atom that
provides the electrons has a lone pair.
Metallic Bonds- Metals
Metallic bonding is the donation of all valence electrons to the
delocalised ‘sea’ of electrons, forming positive metal ions, with full
outer shells. The opposite charges attract, forming strong forces of
electrostatic attraction, like in ionic compounds. Metal ions are
held in a regular structure, with a constantly moving sea, moving
from areas of high negativity to areas of high positivity.
Properties of Metals
• They are highly conductive of heat and electricity as the delocalised
electrons can move through the structure. As they do, they can carry the
current through, or, in the case of heat, collide with ions further along
the structure, giving them more energy, increasing the rate at which
heat moves along the structure.
• They are very strong due to high electrostatic forces of attraction
between ions and electrons.
• They are malleable as the ion layers can slide over each other, whilst
still remaining attracted to the structure, retaining the strength of the
• Their melting and boiling points are high, as it requires a large amount
of energy to separate the structure, due to both strong forces of
attraction and the size of the structure.