How can I write the formula for aluminum oxide?

1 Answer

The formula for aluminum oxide is Al2O3.

Explanation:

The correct answer is Al2O3.

Let us see how we got the answer; Look at the electronic arrangement of Al and O atoms.

Al ( Z= 13) has 13 electrons with following electronic configuration. 1s22s22p63s23p1

It loses three electron in its 3s and 3p subshell to achieve stability and forms ion Al3+.

Al3+ = 1s22s22p6

O ( Z=8) on the other hand has eight electrons and wants to gain two electrons to achieve stable noble gas configuration.Oxygen atom on gaining two electrons forms negative oxide ion, O2 ion.

O ( Z=7) = 1s22s22p4

O2 = 1s22s22p6

Three Oxygen atoms gains two electrons each ( total of six) from two Al atoms, each Al atom loses three electrons (total of six) to three oxygen atom , in this process each Al atom becomes Al3+ ion and Oxygen atom after gaining two electrons becomes O2 ion.

![http://gallery4share.com/a/http://aluminum-ion-lewis-dot-structure.html](https://useruploads.socratic.org/fdem7yigQvykudaJaOs1_Ionic_compound_of_O_and_Al.jpg)

2Al3+ and 3 O2

or the formula is Al2O3.