Question

How many \(3 d\) electrons are found in each of the following elements? a. nickel, \(Z=28\) b. vanadium, \(Z=23\) c. manganese, \(Z=25\) d. iron, \(Z=26\)

Short answer

In the 3d orbitals, there are: a. 8 electrons for Nickel (Ni), b. 3 electrons for Vanadium (V), c. 5 electrons for Manganese (Mn), and d. 6 electrons for Iron (Fe).

Step-by-step solution

Finding the Electron Configuration

To find the electron configurations of nickel (Ni), vanadium (V), manganese (Mn), and iron (Fe), we'll start by using the atomic numbers given (Z) and filling up electron orbitals following the Aufbau principle, which states that electrons are added to orbitals in the order of increasing energy. Ni: \(Z = 28\) V: \(Z = 23\) Mn: \(Z = 25\) Fe: \(Z = 26\) Start with the lowest energy orbital, 1s, and move up through 2s, 2p, 3s, 3p, 4s, and 3d orbitals. After reaching 3d, we need not go further as we are only interested in the number of electrons in the 3d orbitals for each element.

Filling Electrons in Orbitals

Fill the electrons in orbitals for each element while keeping in mind the maximum number of electrons each orbital can hold: 1s (2 electrons), 2s (2 electrons), 2p (6 electrons), 3s (2 electrons), 3p (6 electrons), and 4s (2 electrons). Then start adding electrons in 3d orbitals. Ni: \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^8\) V: \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^3\) Mn: \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^5\) Fe: \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^6\)

Counting the 3d Electrons

Now that we have the electron configurations, we can easily find the number of 3d electrons for each element by looking at the 3d term in the electron configuration. a. Nickel (Ni): There are 8 electrons in 3d orbitals. b. Vanadium (V): There are 3 electrons in 3d orbitals. c. Manganese (Mn): There are 5 electrons in 3d orbitals. d. Iron (Fe): There are 6 electrons in 3d orbitals.

Key concepts

Aufbau Principle

The Aufbau Principle is a fundamental concept in understanding electron configurations in atoms. It provides a guideline for the order in which electrons fill up the available atomic orbitals, from lower to higher energy levels. According to this principle:

• Electrons occupy the lowest energy orbitals first.
• As electrons are added, they fill orbitals in a specific sequence.
• Each orbital can hold a maximum of two electrons with opposite spins.

This process is akin to building up the electron configuration block by block, much like constructing a building from the ground up. The sequence is as follows: 1s, 2s, 2p, 3s, 3p, 4s, and then 3d, with each level supporting a certain number of electrons. The key takeaway from the Aufbau Principle is that understanding electron configurations allows for the prediction of chemical reactions and properties of elements, especially for those looking to understand transition metals and their unique characteristics.

3d Electrons

The electrons found in the 3d sublevel are particularly intriguing because they are a crucial aspect of transition metals, lending them their distinctive properties. The 3d sublevel can hold up to 10 electrons and follows the 4s sublevel in the filling order as dictated by the Aufbau Principle.
When calculating the number of 3d electrons for an element:

• Count the number of electrons after the 4s sublevel in the electron configuration of the element.
• Identify the number after the letter "d" to determine how many electrons occupy the 3d orbital.

For example, with nickel (Ni), which has an electron configuration of \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^8\), there are 8 electrons in the 3d orbital. Understanding the presence and behavior of these 3d electrons is pivotal because they account for the typical metallic characteristics such as conductivity and magnetism, and they play a significant role in chemical bonding.

Transition Metals

Transition metals are elements found in the d-block of the periodic table, characterized by the partial filling of d orbitals. They exhibit unique properties that differentiate them significantly from main group elements:

• They typically have high melting and boiling points.
• These metals often display variable oxidation states.
• Many form colored compounds and are known for their catalytic activity.

The electron configuration of transition metals, particularly the occupation of the 3d orbitals, influences these properties. For instance, manganese (Mn), with its 3d^5 configuration, plays a vital role in numerous biochemical reactions.
Transition metals are essential in industrial applications due to their conductivity, malleability, and ability to form various alloys. Understanding the electron configuration, including the configuration nuances of the 3d electrons, enhances comprehension of their chemical behavior and utility in applications such as electronics, construction, and nanotechnology.