Final answer:
In a molecule with the formula AX2E, there are two bonding domains and one non-bonding domain, resulting in a total of three electron domains.
Step-by-step explanation:
The question you've asked pertains to the number of electron domains in a molecule with the molecular formula AX2E. An electron domain can be either a bond (single, double, or triple) or a lone pair of electrons. For the molecule AX2E, the 'A' represents the central atom, 'X' are the atoms bonded to 'A', and 'E' represents a lone pair of electrons on the central atom.
In the case of AX2E, there are two bonding domains from the 'AX' bonds and one non-bonding domain from the 'E', which is the lone pair. Hence, there is a total of three electron domains.