Complete the given reaction: 

4Al  +  3O₂ → ?

2Al₂O₃

The correct answer is option 2. 2Al₂O₃.

The given reaction \(4\text{Al} + 3\text{O}_2 \rightarrow 2\text{Al}_2\text{O}_3\) represents the reaction between aluminum (\(Al\)) and oxygen gas (\(O_2\)) to form aluminum oxide (\(Al_2O_3\)). Let us break down this reaction and understand it:

1. Aluminum (Al): Aluminum is a metal with the atomic number 13 and belongs to Group 13 of the periodic table. It is a highly reactive metal, capable of reacting with oxygen in the air.

2. Oxygen gas (\(O_2\)): Oxygen is a diatomic molecule, commonly found in the atmosphere. It is highly reactive and readily participates in various chemical reactions.

3. Reaction: When aluminum (\(Al\)) is heated or exposed to oxygen gas (\(O_2\)), it undergoes a combustion reaction, resulting in the formation of aluminum oxide (\(Al_2O_3\)). The balanced chemical equation for this reaction is:

\[ 4\text{Al} + 3\text{O}_2 \rightarrow 2\text{Al}_2\text{O}_3 \]

4. Interpretation: The stoichiometric coefficients in the balanced equation represent the mole ratios of reactants and products. In this case, it indicates that 4 moles of aluminum react with 3 moles of oxygen gas to produce 2 moles of aluminum oxide. This ratio is derived from the conservation of mass principle, ensuring that the number of atoms of each element remains constant on both sides of the equation.

5. Aluminum Oxide (\(Al_2O_3\)): Aluminum oxide is a compound composed of aluminum and oxygen atoms. It is a white or colorless crystalline solid with high melting and boiling points. Aluminum oxide is commonly known as alumina and is widely used in various industrial applications, including as an abrasive, refractory material, and as the primary component in the production of aluminum metal through the Bayer process and Hall–Héroult process.

Overall, the reaction \(4\text{Al} + 3\text{O}_2 \rightarrow 2\text{Al}_2\text{O}_3\) represents the formation of aluminum oxide through the combustion of aluminum metal in the presence of oxygen gas.