Problem 7 - Chemistry and Chemical Reactivity

Question

Use noble gas and spdf notations to depict electron configurations for the following metals of the third transition series. (a) Tantalum, Ta. The metal and its alloys resist corrosion and are often used in surgical and dental tools. (b) Platinum, Pt. This metal was used by pre-Columbian Indians in jewelry. Now it is still used in jewelry but it is also the basis for anticancer drugs and catalysts (such as those in automobile exhaust systems).

Step-by-Step Solution

Answer

Ta: [Xe] 6s^2 4f^{14} 5d^3, Pt: [Xe] 6s^2 4f^{14} 5d^8.

Step 1: Determine Atomic Number of Tantalum

Tantalum (Ta) is an element in the periodic table with an atomic number of 73. This atomic number indicates the number of protons and electrons in a neutral atom of Tantalum.

Step 2: Identify Noble Gas Preceding Tantalum

The noble gas that comes before Tantalum is Xenon (Xe), which has an atomic number of 54. We will use Xenon as the preceding noble gas in the electron configuration of Tantalum.

Step 3: Count Additional Electrons Beyond Xenon

After the noble gas Xenon, we need to account for the additional electrons in Tantalum (73 total electrons). This means we need to consider 73 - 54 = 19 electrons beyond Xenon's electron configuration.

Step 4: Write Electron Configuration for Additional Electrons in Tantalum

After Xenon, the additional 19 electrons are distributed as follows: - 6s: 2 electrons- 4f: 14 electrons- 5d: 3 electronsTherefore, the electron configuration beyond Xenon is: \(6s^2\, 4f^{14}\, 5d^3\).

Step 5: Combine Noble Gas and spdf Notations for Tantalum

Combine the Xenon core with the additional electrons to get the full electron configuration for Tantalum: \[ \text{[Xe]}\, 6s^2\, 4f^{14}\, 5d^3 \].

Step 6: Determine Atomic Number of Platinum

Platinum (Pt) has an atomic number of 78. This indicates the number of protons and electrons in a neutral atom of Platinum.

Step 7: Identify Noble Gas Preceding Platinum

The noble gas preceding Platinum is Xenon (Xe), which has an atomic number of 54, just like in Tantalum's case.

Step 8: Count Additional Electrons Beyond Xenon for Platinum

After Xenon, Platinum has 78 - 54 = 24 additional electrons.

Step 9: Write Electron Configuration for Additional Electrons in Platinum

The distribution beyond Xenon for Platinum is:- 6s: 2 electrons- 4f: 14 electrons- 5d: 8 electronsTherefore, the electron configuration for these electrons is: \(6s^2\, 4f^{14}\, 5d^8\).

Step 10: Combine Noble Gas and spdf Notations for Platinum

Combine the Xenon core with the additional electrons to get the full electron configuration for Platinum: \[ \text{[Xe]}\, 6s^2\, 4f^{14}\, 5d^8 \].

Key Concepts

Noble Gas Notation

Noble gas notation is a shorthand way to write the electron configuration of an element by using the electron configuration of the last noble gas that preceded it in the periodic table.
This method helps to simplify complex electron configurations by abbreviating the core electrons. Noble gases are the elements found in Group 18 of the periodic table, like Helium (He), Neon (Ne), Argon (Ar), and Xenon (Xe).
For example, instead of writing the full electron configuration for Tantalum (73 electrons), we use the noble gas Xenon (54 electrons) to represent the core configuration as [Xe].
The remaining electrons beyond Xenon are added to complete the configuration. This approach not only saves time but also provides a starting point that is stable and chemically inert, reflecting the filled electron shells of noble gases.

SPDF Notation

SPDF notation describes the distribution of electrons across different atomic orbitals: s, p, d, and f.
The letters correspond to different shapes of the orbitals where electrons can reside within an atom. - **s-orbitals:** Can hold 2 electrons and are spherical in shape. - **p-orbitals:** Can hold 6 electrons total, with 3 possible shapes (px, py, pz) that are dumbbell-shaped. - **d-orbitals:** Hold up to 10 electrons and can have complex shapes. - **f-orbitals:** Can accommodate 14 electrons and are even more complex in shape. For Tantalum, the complete SPDF configuration beyond Xenon is expressed as: 6s² 4f¹⁴ 5d³.
Understanding SPDF notation is key to predicting and explaining the chemical behavior of elements.

Transition Metals

Transition metals are elements found in the d-block of the periodic table, specifically in Groups 3-12.
These metals are characterized by their ability to form a broad set of oxidation states due to the presence of d-electrons. They often display:

• High melting and boiling points.
• Great ability to conduct electricity and heat.
• Colorful compounds due to d-d electron transitions.

Tantalum and Platinum are both transition metals, widely known for their use in various industrial applications.
Tantalum is resistant to corrosion and used in medical tools, while Platinum is valued in jewelry and catalytic converters.

Periodic Table

The periodic table is a comprehensive chart that organizes all known elements based on their atomic number.
It arranges elements into rows (periods) and columns (groups) that display periodic chemical properties. Key Features:

• Elements in the same column have similar chemical characteristics.
• The table predicts elements' properties and their potential compounds.
• Transition metals are located in the central block (d-block) of the table.

For example, finding Tantalum and Platinum on the periodic table helps to easily identify their atomic numbers and group properties, such as being transition metals.
The table serves as a tool for chemists to understand the relationships between various elements effortlessly.

Atomic Number

An atomic number is the number of protons found in the nucleus of an atom, which also equals the number of electrons in a neutral atom.
This number is crucial as it uniquely identifies an element and determines its position in the periodic table. For instance: - Tantalum has an atomic number of 73, meaning it has 73 protons and 73 electrons.
- Platinum has an atomic number of 78, possessing 78 protons and electrons. The atomic number influences:

• The element's chemical properties.
• Its placement on the periodic table.
• The energy level and position of electrons in the atom.

With atomic numbers, scientists can predict how elements will interact with each other, which is fundamental to understanding chemical reactions and bonding.