What is the charge on the ion formed by aluminum?
A) 3–
B) 3+
C) 5–
D) 13+
E) None of the above
The correct answer and explanation is :
Correct Answer: B) 3+
Explanation (300 words):
Aluminum is a metallic element with the atomic number 13, meaning it has 13 protons in its nucleus and, in a neutral atom, 13 electrons surrounding the nucleus. These electrons are arranged in energy levels or shells according to the pattern: 2 in the first shell, 8 in the second, and 3 in the third (2-8-3).
Aluminum is located in Group 13 of the periodic table, which means it has three valence electrons—the electrons in its outermost shell. When elements react, they tend to gain or lose electrons in order to achieve a stable electron configuration, often resembling the nearest noble gas (which has a full outer shell).
For aluminum, the nearest noble gas is neon, which has a configuration of 2-8. To achieve this stable configuration, aluminum loses its three valence electrons. When it does so, it no longer has the same number of electrons and protons—now it has 10 electrons and 13 protons, resulting in a net positive charge of +3. This is because there are three more protons than electrons.
Thus, the ion formed by aluminum is written as Al³⁺, and it is called a cation because it carries a positive charge. This is a very common and stable oxidation state for aluminum, and it plays a key role in compounds like aluminum oxide (Al₂O₃) and aluminum sulfate (Al₂(SO₄)₃).
To clarify the incorrect options:
- A) 3–: This would be an anion, but metals like aluminum don’t gain electrons.
- C) 5– and D) 13+: These are highly unrealistic and chemically implausible.
- E) None of the above: Incorrect because option B is correct.
Therefore, the correct answer is B) 3+.
