Question

In which of the following is(are) the electron configuration(s) correct for the species indicated? a. \(\mathrm{Cu} \quad[\mathrm{Ar}] 4 s^{2} 3 d^{9}\) b. \(\mathrm{Fe}^{3+} \quad[\mathrm{Ar}] 3 d^{5}\) c. \(\mathrm{Co} \quad[\mathrm{Ar}] 4 s^{2} 3 d^{7}\) d. La \(\quad[\mathrm{Ar}] 6 s^{2} 4 f^{1}\) e. \(\mathrm{Pt}^{2+} \quad[\mathrm{Xe}] 4 f^{14} 5 d^{8}\)

Short answer

#tag_title#Step 2: Calculate the electron configurations for each species.#tag_content#Using the atomic numbers, we can now write the electron configurations for each species, including charge considerations. a. Cu should have the electron configuration: \([\mathrm{Ar}] 4s^1 3d^{10}\) due to the increased stability of a filled d orbital. b. Fe³⁺ would have 3 less electrons than neutral Fe, so its electron configuration should be: \([\mathrm{Ar}] 3d^5\). c. Co should have the electron configuration: \([\mathrm{Ar}] 4s^2 3d^7\). d. La should have the electron configuration: \([\mathrm{Xe}] 6s^2 5d^1\), since it is the first member of the d-block after the f-block. e. Pt²⁺ would have 2 less electrons than neutral Pt, so its electron configuration should be: \([\mathrm{Xe}] 4f^{14} 5d^{8}\). #tag_title#Step 3: Compare calculated configurations with given configurations.#tag_content#Now, compare the calculated electron configurations with the given ones in the question. a. Given: \([\mathrm{Ar}] 4s^2 3d^9\), Correct: \([\mathrm{Ar}] 4s^1 3d^{10}\) - Incorrect b. Given: \([\mathrm{Ar}] 3d^5\), Correct: \([\mathrm{Ar}] 3d^5\) - Correct c. Given: \([\mathrm{Ar}] 4s^2 3d^7\), Correct: \([\mathrm{Ar}] 4s^2 3d^7\) - Correct d. Given: \([\mathrm{Ar}] 6s^2 4f^1\), Correct: \([\mathrm{Xe}] 6s^2 5d^1\) - Incorrect e. Given: \([\mathrm{Xe}] 4f^{14} 5d^{8}\), Correct: \([\mathrm{Xe}] 4f^{14} 5d^{8}\) - Correct Based on the comparison, options b, c, and e have the correct electron configurations.

Step-by-step solution

Find the atomic number of the given species.

In order to find the correct electron configuration, we need to know the atomic number of each species. Use the periodic table to find the atomic number of each element. Cu: Atomic Number = 29 Fe: Atomic Number = 26 Co: Atomic Number = 27 La: Atomic Number = 57 Pt: Atomic Number = 78

Key concepts

atomic number

The atomic number of an element is a fundamental concept in chemistry. It refers to the number of protons in the nucleus of an atom. This number is unique for each element and primarily determines its identity and position in the periodic table. Understandably, knowing the atomic number allows you to deduce various properties of the element, including its electron configuration.

For instance, Copper (Cu), with an atomic number of 29, will have 29 electrons in a neutral atom. Since electrons fill orbitals in a specific order, the atomic number helps in predicting the element's electron configuration. In essence, the atomic number serves as a basic identifier for each chemical element and plays a crucial role in the organization of the periodic table.

periodic table

The periodic table is a systematic arrangement of elements. Elements are listed in order of increasing atomic numbers, which helps to clarify the recurring (periodic) trends in element properties. This arrangement allows us to group elements with similar properties together.

• Groups: Vertical columns are called groups, indicating elements with similar chemical properties.
• Periods: Horizontal rows are known as periods. Moving across a period, the properties of elements gradually change.
• Blocks: The table is divided into blocks, corresponding to the filling of different electron orbitals (s, p, d, f).

The periodic table provides invaluable insights into electron configurations and valences of elements, which aid in understanding chemical reactions and bonding. For example, transition metals are found in the d-block of the periodic table, characterized by partially filled d orbitals.

transition metals

Transition metals are a group of elements located in the center of the periodic table, specifically in the d-block. These metals are known for their ability to form a variety of different oxidation states and to create complex ions.

• Electron Configuration: Transition metals typically have a filled or partially filled d orbital.
• Properties: They are often shiny, have high melting points, and conduct electricity well.
• Common Elements: Iron (Fe), Copper (Cu), and Cobalt (Co) are well-known transition metals.

Transition metals play crucial roles in industrial applications and biological systems due to their diverse chemical properties. The wide range of oxidation states they exhibit makes them potent catalysts in many chemical reactions. Understanding their electron configurations helps chemists predict their behavior in various chemical processes.