Question

Find three examples of ions in the periodic table that have an electron configuration of \(n d^{8}(n=3,4,5, \ldots)\).

Short answer

Three examples of ions in the periodic table that have an electron configuration of \(n d^{8}\) are: 1. Ni(II): \([Ar] 3d^{8}\), n = 3 2. Pd(II): \([Kr] 4d^{8}\), n = 4 3. Pt(II): \([Xe] 4f^{14}5d^{8}\), n = 5

Step-by-step solution

Understand the electron configuration notation

\(n d^{8}\) indicates that there are 8 electrons in the d-orbital of the nth energy level. The value of n can be 3, 4, 5, etc. So, we need to look for ions in the periodic table which have 8 electrons in the d-orbital of one of the energy levels.

Investigate the transition metals

The elements that commonly have electrons in d-orbitals are the transition metals. They can be found in the d-block of the periodic table, groups 3 to 12. We will focus on these elements to find ions with the desired electron configuration.

Find elements that can lose electrons to achieve \(n d^{8}\) configuration

Some transition metals can lose a specific number of electrons to achieve the desired electron configuration. Let's explore some examples: - Nickel (Ni, atomic number 28) has an electron configuration of \([Ar] 3d^{8}4s^{2}\). Upon losing two electrons from its 4s orbital, it forms Ni(II) ion, which has a configuration of \([Ar] 3d^{8}\), where n=3. - Palladium (Pd, atomic number 46) has an electron configuration of \([Kr] 4d^{10}5s^0\). In this case, it has to lose two electrons from its 4d orbital to form Pd(II) ion, which has a configuration of \([Kr] 4d^{8}\), where n=4. - Platinum (Pt, atomic number 78) has an electron configuration of \([Xe] 4f^{14}5d^{9}6s^1\). To achieve the desired configuration, it has to lose one electron from its 5d orbital and one electron from its 6s orbital to form Pt(II) ion, which has a configuration of \([Xe] 4f^{14}5d^{8}\), where n=5.

Summary of findings

Here are the three ions with an electron configuration of \(n d^{8}\): 1. Ni(II): \([Ar] 3d^{8}\), n = 3 2. Pd(II): \([Kr] 4d^{8}\), n = 4 3. Pt(II): \([Xe] 4f^{14}5d^{8}\), n = 5

Key concepts

Transition Metals

Transition metals are a group of elements found in the middle of the periodic table, specifically in groups 3 to 12, occupying the 'd-block'. These elements are known for their ability to form colorful compounds, their use as catalysts, and most importantly, for their unique electron configurations and the ability to exist in multiple oxidation states.

Understanding transition metals is essential for grasping the foundation of coordination chemistry and the behavior of electrons in the 'd-orbital', which often influences the chemical and physical properties of these elements. For example, elements like iron, copper, and gold are transition metals with varying electron configurations that contribute to their distinctive properties such as magnetism and conductivity.

These metals frequently have valence electrons in two different types of orbitals, namely 'd' and 's'. As they have a tendency to lose electrons and form positively charged ions, their electron configurations can change significantly from their neutral state. This variability is crucial when solving problems related to electron configurations in transition metals, such as finding ions with a specific 'd' orbital occupancy.

d-Orbital

The 'd-orbital' is one of the types of orbitals found in atoms where electrons can reside. Each d-orbital can hold up to two electrons, with a total capacity of 10 electrons when all five of the d-orbitals are filled. These orbitals are filled after the 's' orbital of the same energy level, following Hund's rule for the order of filling electron orbitals.

In transition metals, the d-orbital plays a significant role in the chemical and physical characteristics of the element. When discussing electron configurations such as the 'n d^8' configuration mentioned in the exercise, we focus on the number and arrangement of electrons in these orbitals. The configuration 'n d^8' implies that there are 8 electrons distributed across the five orbitals of the d-subshell in any given energy level 'n'.

Students must note the importance of the d-orbital occupancy in dictating the geometry and the nature of bonds these atoms can form in compounds. For instance, a 'd^8' configuration can lead to square planar or tetrahedral geometries in complexes, influencing the metal's reactivity and interactions.

Periodic Table

The periodic table is a tabular display of chemical elements organized based on their atomic number, electron configurations, and recurring chemical properties. Elements are ordered into periods (rows) and groups (columns).

For students dealing with electron configurations, the periodic table serves as an essential guide to understanding how these configurations change from one element to another, following a general pattern called the Aufbau principle. The table also neatly separates the main group elements from the transition metals which, as mentioned earlier, comprise the d-block of the table, groups 3 through 12.

The key takeaway for students from the periodic table, in the context of our exercise, is noticing the trends and patterns in electron configurations across different elements. It acts as a map that allows students to predict how electrons are distributed in an atom or ion by simply looking at its position on the table, which is particularly useful when finding ions with specific electron configurations such as 'n d^8'.