Determine the chemical formula for the ionic compound that forms between aluminum and oxygen.
The correct answer and explanation is :
Answer:
The chemical formula for the ionic compound formed between aluminum and oxygen is Al₂O₃.
Detailed Explanation (300+ words):
When determining the chemical formula of an ionic compound, it is important to consider the charges (oxidation numbers) of the ions involved. Ionic compounds must be electrically neutral overall, meaning the total positive charge must balance the total negative charge.
Let’s start with aluminum (Al):
- Aluminum is a metal found in Group 13 (or IIIA) of the periodic table.
- Elements in this group typically lose three electrons to achieve a stable electron configuration, forming a +3 cation (Al³⁺).
Now, consider oxygen (O):
- Oxygen is a nonmetal found in Group 16 (or VIA).
- Oxygen atoms tend to gain two electrons to fill their outer electron shell, forming a –2 anion (O²⁻).
Now, to create a neutral compound:
- We need to balance the total positive and negative charges.
- Each Al³⁺ ion contributes +3 charge, and each O²⁻ ion contributes –2 charge.
- Find the least common multiple (LCM) of the charges, which is 6.
- To reach a total charge of +6, we need two aluminum ions (+3 × 2 = +6).
- To reach a total charge of –6, we need three oxygen ions (–2 × 3 = –6).
Thus, two Al³⁺ ions and three O²⁻ ions combine to form a neutral compound:
- Al₂O₃ (aluminum oxide).
Summary of the steps:
- Identify the charges of the ions: Al³⁺ and O²⁻.
- Find the smallest common multiple of their charges (6).
- Adjust the ratio: 2 aluminum ions and 3 oxygen ions.
- Write the formula without showing charges: Al₂O₃.
This formula ensures the total positive charge (+6) and the total negative charge (–6) cancel out, making the compound stable and electrically neutral.
Al₂O₃ is commonly known as aluminum oxide, and it appears naturally as a component in minerals like corundum and sapphire.