Topic 4: Chemical bonding and structure (13.5 hours) - 4.1 Ionic bonding and structure

Nature of science: Use theories to explain natural phenomena-molten ionic compounds conduct electricity but solid ionic compounds do not. The solubility and melting points of ionic compounds can be used to explain observations. (2.2)


Positive ions (cations) form by metals losing valence electrons.

Negative ions (anions) form by non-metals gaining electrons.

The number of electrons lost or gained is determined by the electron configuration of the atom.

The ionic bond is due to electrostatic attraction between oppositely charged ions.

Under normal conditions, ionic compounds are usually solids with lattice structures.

Applications and skills

Deduction of the formula and name of an ionic compound from its component ions, including polyatomic ions.

Explanation of the physical properties of ionic compounds (volatility, electrical conductivity and solubility) in terms of their structure.


Students should be familiar with the names of these polyatomic ions: NH4+,OH-, NO3-, HCO3-, CO32-, SO42- and PO43-.