Question

Write out the electron configuration for each of the following metal ions: (a) \(\mathrm{Li}^{+}\) (b) \(\mathrm{Al}^{3+}\) (c) \(\mathrm{Ca}^{2+}\) (d) \(\mathrm{Mg}^{2+}\)

Short answer

(a) i^+: s^2 (b) l^{3+}: s^2 2s^2 2p^6 (c) a^{2+}: s^2 2s^2 2p^6 3s^2 3p^6 (d) g^{2+}: s^2 2s^2 2p^6

Step-by-step solution

Understanding the Problem

To write the electron configuration of metal ions, we must start with the electron configuration of the neutral atom and then remove electrons according to the charge of the ion. Electrons are removed first from the outermost shell.

Write Electron Configuration for Neutral Atoms

First, find the electron configuration of the neutral atoms for each element. (a) - Lithium (i): 3 electrons -> s^2 2s^1 (b) - Aluminum (l): 13 electrons -> s^2 2s^2 2p^6 3s^2 3p^1 (c) - Calcium (a): 20 electrons -> s^2 2s^2 2p^6 3s^2 3p^6 4s^2 (d) - Magnesium (g): 12 electrons -> s^2 2s^2 2p^6 3s^2

Adjust Electron Count for Ions

Remove electrons from the outermost shell to form the metal ions. The number of electrons removed is equal to the positive charge of the ion. (a) - i^+: Remove 1 electron from 2s^1 -> s^2 (b) - l^{3+}: Remove 3 electrons from 3s^2 3p^1 -> s^2 2s^2 2p^6 (c) - a^{2+}: Remove 2 electrons from 4s^2 -> s^2 2s^2 2p^6 3s^2 3p^6 (d) - g^{2+}: Remove 2 electrons from 3s^2 -> s^2 2s^2 2p^6

Conclusion

The electron configurations for the metal ions are: (a) i^+: s^2 (b) l^{3+}: s^2 2s^2 2p^6 (c) a^{2+}: s^2 2s^2 2p^6 3s^2 3p^6 (d) g^{2+}: s^2 2s^2 2p^6

Key concepts

Metal Ions

Metal ions are simply atoms that have lost one or more of their electrons. This loss of electrons results in a net positive charge, making them cations. For example, when a lithium atom loses one electron, it becomes a lithium ion (\(\mathrm{Li}^{+}\)). Metal ions are crucial in chemistry because they contribute to the reactivity and formation of compounds.

Understanding metal ions involves recognizing their role in electron configurations. Electrons are arranged in shells around an atom's nucleus, and it is the electrons in the outermost shells that are typically removed to form ions.

Keep in mind that:

• The process of electron removal is guided by the ion's charge. A positive ion indicates electron loss.
• Metal ions are typically formed from elements found on the left side of the periodic table, primarily the alkali and alkaline earth metals.
• These ions play a significant role in the chemical behavior and properties of the elements.

Periodic Table

The periodic table is an essential tool for understanding elements and their interactions. It organizes elements based on atomic number, electron configuration, and recurring chemical properties. This makes it easier to predict how different elements will behave in reactions and form ions.

For the purpose of electron configuration, the periodic table helps identify the distribution of electrons across different energy levels and orbitals. When dealing with metal ions, find the element's location on the table to determine its neutral electron configuration. Then, use this information to guide the removal of electrons when forming ions.

Here are some key things to note about the periodic table:

• The rows, known as periods, correlate to the number of electron shells an element's atoms possess.
• The columns, or groups, share similar properties and valence electron configurations.
• Elements tend to form ions by losing or gaining electrons to achieve a stable noble gas electron configuration.

In terms of electron configuration, the transition metals and the representative elements (s- and p-blocks) are the most focused upon, as they most frequently form ions.

Ionic Charge

Ionic charge is a fundamental concept when dealing with metal ions. It refers to the net electrical charge an ion has, which results from the loss or gain of electrons. When metal atoms lose electrons, they form positively charged ions, known as cations.

Calculating and understanding the ionic charge involves determining the difference between the number of protons (which remain constant) and electrons (which vary in ions).

Consider the following points regarding ionic charge:

• The positive charge of an ion corresponds to the number of electrons removed. For example, a magnesium ion (\(\mathrm{Mg}^{2+}\)) has lost 2 electrons, resulting in a 2+ charge.
• The ionic charge influences the reactivity and bonding potential of an ion. Higher charges typically result in stronger bonds and greater interaction in reactions.
• Knowing the ionic charge helps in writing proper chemical formulas and understanding the stoichiometry of reactions involving these ions.

Understanding ionic charges is essential in predicting how different metal ions will interact in chemical reactions, which ultimately influences compound formation and elemental behavior.