To determine the compounds that aluminum (Al) can form to dissolve in water, we will consider aluminum combining with each of the given ions: oxide ([tex]\( O^{2-} \)[/tex]), sulfide ([tex]\( S^{2-} \)[/tex]), and nitrate ([tex]\( NO_3^{-} \)[/tex]).
Aluminum typically forms a [tex]\( Al^{3+} \)[/tex] ion. We must combine this [tex]\( Al^{3+} \)[/tex] ion with each of the given anions to predict the resulting compounds.
### Combining Aluminum with Oxide ([tex]\( O^{2-} \)[/tex])
1. Aluminum has a charge of [tex]\( +3 \)[/tex] (i.e., [tex]\( Al^{3+} \)[/tex]).
2. The oxide ion has a charge of [tex]\( -2 \)[/tex] (i.e., [tex]\( O^{2-} \)[/tex]).
To balance the charges, we need a total positive charge and total negative charge that are equal. The least common multiple of 3 and 2 is 6. Therefore:
- Two [tex]\( Al^{3+} \)[/tex] ions will provide a total positive charge of [tex]\( 2 \times (+3) = +6 \)[/tex].
- Three [tex]\( O^{2-} \)[/tex] ions will provide a total negative charge of [tex]\( 3 \times (-2) = -6 \)[/tex].
Thus, the compound formed is [tex]\( Al_2O_3 \)[/tex] (Aluminum oxide).
### Combining Aluminum with Sulfide ([tex]\( S^{2-} \)[/tex])
1. Aluminum has a charge of [tex]\( +3 \)[/tex] (i.e., [tex]\( Al^{3+} \)[/tex]).
2. The sulfide ion has a charge of [tex]\( -2 \)[/tex] (i.e., [tex]\( S^{2-} \)[/tex]).
As with the oxide ion, we need to balance the charges. Using the least common multiple of 3 and 2, which is 6:
- Two [tex]\( Al^{3+} \)[/tex] ions will give a total positive charge of [tex]\( 2 \times (+3) = +6 \)[/tex].
- Three [tex]\( S^{2-} \)[/tex] ions will give a total negative charge of [tex]\( 3 \times (-2) = -6 \)[/tex].
Thus, the compound formed is [tex]\( Al_2S_3 \)[/tex] (Aluminum sulfide).
### Combining Aluminum with Nitrate ([tex]\( NO_3^{-} \)[/tex])
1. Aluminum has a charge of [tex]\( +3 \)[/tex] (i.e., [tex]\( Al^{3+} \)[/tex]).
2. The nitrate ion has a charge of [tex]\( -1 \)[/tex] (i.e., [tex]\( NO_3^{-} \)[/tex]).
For the charges to balance:
- One [tex]\( Al^{3+} \)[/tex] ion will require three [tex]\( NO_3^{-} \)[/tex] ions to balance out its [tex]\( +3 \)[/tex] charge.
Thus, the compound formed is [tex]\( Al(NO_3)_3 \)[/tex] (Aluminum nitrate).
### Conclusion
The compounds that aluminum (Al) forms to dissolve in water with the given ions are:
- Aluminum oxide: [tex]\( Al_2O_3 \)[/tex]
- Aluminum sulfide: [tex]\( Al_2S_3 \)[/tex]
- Aluminum nitrate: [tex]\( Al(NO_3)_3 \)[/tex]
