Problem 14 - Chemistry: The Central Science in SI Units, Global Edition

Question

Among the period 4 transition metals \((\mathrm{Sc}-\mathrm{Zn}),\) which elements do not form ions where there are partially filled \(3 d\) orbitals?

Step-by-Step Solution

Answer

The period 4 transition metals that do not form ions with partially filled 3d orbitals are Scandium (Sc), Titanium (Ti), Vanadium (V), Copper (Cu), and Zinc (Zn).

Step 1: Write down the electron configurations of the period 4 transition metals

We can determine the electron configurations of the period 4 transition metals through the periodic table: 1. Scandium (Sc): [Ar] 4s² 3d¹ 2. Titanium (Ti): [Ar] 4s² 3d² 3. Vanadium (V): [Ar] 4s² 3d³ 4. Chromium (Cr): [Ar] 4s¹ 3d⁵ 5. Manganese (Mn): [Ar] 4s² 3d⁵ 6. Iron (Fe): [Ar] 4s² 3d⁶ 7. Cobalt (Co): [Ar] 4s² 3d⁷ 8. Nickel (Ni): [Ar] 4s² 3d⁸ 9. Copper (Cu): [Ar] 4s¹ 3d¹⁰ 10. Zinc (Zn): [Ar] 4s² 3d¹⁰

Step 2: Identify the elements that form stable cations without partially filled 3d orbitals

Now, we need to determine which of these elements do not form ions with partially filled 3d orbitals. To do this, we'll examine their possible cations and the resulting electron configurations: 1. Scandium (Sc): Sc³⁺ has the electron configuration [Ar], with no remaining 3d electrons. 2. Titanium (Ti): Ti⁴⁺ has the electron configuration [Ar], with no remaining 3d electrons. 3. Vanadium (V): V⁵⁺ has the electron configuration [Ar], with no remaining 3d electrons. 4. Chromium (Cr): Cr²⁺ has the electron configuration [Ar] 3d⁴. 5. Manganese (Mn): Mn²⁺ has the electron configuration [Ar] 3d⁵. 6. Iron (Fe): Fe³⁺ has the electron configuration [Ar] 3d⁵. 7. Cobalt (Co): Co³⁺ has the electron configuration [Ar] 3d⁶. 8. Nickel (Ni): Ni²⁺ has the electron configuration [Ar] 3d⁸. 9. Copper (Cu): Cu⁺ has the electron configuration [Ar] 3d¹⁰. 10. Zinc (Zn): Zn²⁺ has the electron configuration [Ar] 3d¹⁰.

Step 3: List the elements that do not form ions with partially filled 3d orbitals

From the information in Step 2, we can determine that Scandium (Sc), Titanium (Ti), Vanadium (V), Copper (Cu), and Zinc (Zn) are the period 4 transition metals that do not form ions with partially filled 3d orbitals.

Key Concepts

Electron Configuration

Electron configuration refers to how electrons are distributed in different atomic orbitals. Understanding electron configuration is critical to comprehending chemical properties and behaviors. For atoms in their ground state, electrons are filled in such a way to achieve the lowest possible energy.
For the period 4 transition metals, electron configurations start with the noble gas configuration of Argon \(\text{[Ar]}\), followed by additional electrons in the 4s and 3d orbitals.

• Scandium (Sc): \([\text{Ar}] \ 4s^2 \ 3d^1\)
• Titanium (Ti): \([\text{Ar}] \ 4s^2 \ 3d^2\)
• Vanadium (V): \([\text{Ar}] \ 4s^2 \ 3d^3\)
• ... ending with Zinc (Zn): \([\text{Ar}] \ 4s^2 \ 3d^{10}\)

When filling the d shell, once the 4s orbital is filled, electrons begin populating the 3d orbitals. However, due to electron-electron interactions and energy considerations, there are exceptions like Chromium (Cr) and Copper (Cu), where an electron from the 4s is used to half fill or completely fill the 3d orbital for added stability.

Period 4 Elements

Period 4 elements on the periodic table are fascinating, particularly the transition metals from Scandium (Sc) to Zinc (Zn). These elements have electrons entering the 3d sublevel, setting them apart from other elements.
They are known for their unique chemical behaviors and variable oxidation states. In period 4, transition metals' noteworthy features include:

• High melting points
• Variable oxidation states
• Formation of colored compounds
• Magnetic properties, particularly among the first few elements

The filling of the 3d orbitals confers unique characteristics. For instance, the incomplete d orbitals allow transition metals to form various ions and exhibit distinct magnetic and hallucinogenic properties. Transition metals in period 4 also play crucial roles in biological systems and industrial processes, leveraging their ability to form stable complex ions.

Ion Formation

Ion formation in transition metals is an intriguing process due to their variable oxidation states. When transition metals form ions, they typically lose electrons from both the s and d orbitals. The number of electrons removed corresponds to their oxidation state.
For example:

• Scandium (Sc) loses 3 electrons to form \(\text{Sc}^{3+}\), resulting in \(\text{[Ar]}\)
• Titanium (Ti) can form \(\text{Ti}^{4+}\), emptying the 3d orbital
• Copper (Cu) forms a stable \(\text{Cu}^+ \) ion with a full 3d orbital \(\text{[Ar] 3d}^{10}\)

Unlike main group metals that typically form one type of ion, transition metals can form numerous ions with different charges. The differing ion charges affect the color, magnetism, and reactivity of the transition compounds. A practical example is iron, which can exist as \(\text{Fe}^{2+}\) or \(\text{Fe}^{3+}\), contributing to its versatility in chemical reactions and forming diverse compounds, essential for various industrial applications.