Answer:
Question #1: How many valence electrons in Aluminum? Is it 3?
------> Yes, aluminum has 3 valence electrons.
Question #2: How many valence electron in Sulfur? Is it 6?
-----> Yes, sulfur has 6 valence electrons.
Question #3: What type of bonds do these form? Is it covalent or ionic?
-----> Covalent bonds generally occur between 2 nonmetals. Ionic bonds generally occur between a metal and a nonmetal. Aluminum is a metal and sulfur is a nonmetal. Therefore, an ionic bond would form.
Question #4: How many aluminum atoms will you need? 1, 2, or 3?
-----> Atoms become ions in order to achieve a full octet of valence electrons (8 valence electrons). Since aluminum atoms have 3 valence electrons, they are likely to donate these electrons during ionization. As such, aluminum ions look like this: Al³⁺. Since sulfur atoms have 6 valence electrons, they are likely to receive 2 electrons during ionization. As such, sulfur ions look like this: S²⁻.
-----> The ionic compound formed will be Al₂S₃. There would be 2 aluminum atoms because this arrangement allows for the ionic compound to have an overall charge of 0.
Aluminum = +3
Sulfur = -2
+3 + 3 + (-2) + (-2) + (-2) = 0
Question #5: How many sulfur atoms will you need? 1, 2, or 3?
-----> As stated previously the resulting ionic compound is Al₂S₃. There would be 3 sulfur atoms to balance the charges.