Final answer:
To form the compound Al2O3, 6 electrons are transferred: two aluminum atoms donate a total of 6 electrons (2 × 3 electrons), while three oxygen atoms accept the same number (3 × 2 electrons).
Step-by-step explanation:
The question asks how many total electrons must be transferred to form one formula unit of the compound Al2O3. The process of forming aluminum oxide involves the transfer of electrons between aluminum atoms and oxygen atoms. Each aluminum atom can donate 3 electrons since it forms a 3+ cation (Al3+). Each oxygen atom needs 2 electrons to reach an octet, forming a 2- anion (O2-).
To form the neutral compound Al2O3, we would need 2 aluminum ions (2 Al3+ each donating 3 electrons) to pair with 3 oxide ions (3 O2- each accepting 2 electrons). Therefore, a total of 6 electrons are transferred from the aluminum to the oxygen ions to achieve charge balance, as shown by the calculation (2 × 3+) + (3 × 2-) = 0.