Question

How many electrons must an aluminum atom, \(Z=13\), lose to attain a noble gas configuration? Write the symbol for the ion formed.

Short answer

Aluminum must lose 3 electrons to form the ion \( \text{Al}^{3+} \).

Step-by-step solution

Understanding the Problem

An aluminum atom has an atomic number of 13, meaning it has 13 electrons in its neutral state. To attain a noble gas configuration, it needs to achieve the same number of electrons as the nearest noble gas.

Identifying the Nearest Noble Gas

Aluminum is in Group 13 and Period 3 of the periodic table. The nearest noble gas with fewer electrons than aluminum is neon, which has 10 electrons (as its atomic number is 10).

Calculating Electrons to Lose

To determine how many electrons aluminum must lose, subtract the electron count of the nearest noble gas (neon) from aluminum's electron count: \[ 13 - 10 = 3 \]So, aluminum must lose 3 electrons to match the noble gas configuration of neon.

Determine the Ion Formed

When aluminum loses 3 electrons, it forms a positively charged ion, as it has more protons than electrons. The ion formed is represented by the symbol \( \text{Al}^{3+} \), indicating that it has lost 3 electrons.

Key concepts

Noble Gas Configuration

Noble gas configuration refers to the stable arrangement of electrons in the outer shell of a noble gas. Noble gases, located in the far right column of the periodic table, such as helium (He), neon (Ne), argon (Ar), and others, have complete valence electron shells. This complete valence shell makes them extremely stable, meaning they have little tendency to gain or lose electrons.

Many elements will undergo processes to achieve a similar electronic configuration, resulting in more stability. One common way elements stabilize is by losing or gaining electrons to form ions, allowing them to effectively "borrow" the noble gas configuration of a nearby noble gas. This pursuit of stability is a fundamental concept in chemistry and is a key factor in determining how elements interact and bond with one another.

Aluminum Atom

Aluminum is a chemical element positioned in Group 13, Period 3 of the periodic table and is denoted by the symbol Al. An aluminum atom has an atomic number of 13, meaning it possesses 13 protons, and in its neutral state, it also has 13 electrons.

The electronic configuration of an aluminum atom in its ground state can be written as:

• The first shell holds 2 electrons.
• The second shell holds 8 electrons.
• The third shell holds the remaining 3 electrons (2, 8, 3).

The outermost shell, or the valence shell, containing just 3 electrons, makes aluminum reactive, as it seeks to achieve a more stable electron arrangement similar to the noble gases by losing or sharing these electrons.

Electron Loss

When discussing electron loss, it's essential to understand that this process typically results in the formation of positive ions or cations. For aluminum, losing electrons is a favored path to achieving a noble gas configuration.

Aluminum, with its 13 electrons, will lose 3 of these, leaving it with 10 electrons. This loss matches it to the electron count of neon, the nearest noble gas. This transition is driven by aluminum's tendency to reach the more stable, lower-energy state that a full outer electron shell offers.

The loss of 3 electrons results in a charge imbalance in aluminum, leading to the formation of a positively charged ion, specifically denoted as \( \text{Al}^{3+} \). Each electron lost increases the charge by +1, hence a 3+ charge for the aluminum ion.

Atomic Structure

The atomic structure of an element lays the foundation for understanding its behavior in chemical reactions, including ion formation. An atom is composed of a nucleus containing protons and neutrons, surrounded by electrons that orbit this central nucleus in defined energy levels or shells.

The arrangement of these electrons is crucial because it determines the chemical properties and reactivity of the atom.

• The energy levels closest to the nucleus are filled first as they are lower in energy.
• Subsequent electrons populate higher energy levels.

In aluminum's case, its atomic structure includes 3 valence electrons in its outermost shell. The layout of these electrons propels reactions such as electron loss to lead to a stable noble gas configuration. Thus, understanding the atomic structure gives insight into why and how aluminum forms ions like \( \text{Al}^{3+} \), shaping its role in various chemical interactions.