The Electron Configuration: Condensed - Online Tutor, Practice Problems & Exam Prep

Condensed electron configuration is a streamlined method for representing electron arrangements in elements or ions. It begins with the last noble gas preceding the element in question, simplifying the notation. This approach is favored for its efficiency, especially when full ground state configurations are not required. Understanding the periodic table's structure, including the s, p, d, and f blocks, is essential for determining the correct noble gas reference. Mastery of this method is crucial for students studying atomic structure and electron configurations.

The Electron Configuration: Condensed

We're going to say here that the condensed electron configuration is a faster way to write out electron arrangements for elements or ions. We're going to say with condensed electron configurations, we start at the last noble gas before the desired element. And if we take a look here, remember, this is our reimagining of the periodic table. We have our s block where it begins with s1. We have our p block here, our d block here, and our f block down here. With the condensed electron configuration, it's important to know which element we are being asked to find the electron configuration of, and what's the noble gas before it. We're going to say moving forward this will be the primary method to write electron configurations, because it's the faster, easier way to do it. Unless they say full ground state electron configuration, we usually just assume that this is the method they want us to write the electron configuration. So now that we know what the condensed electron configuration is, click on the next video, and let's get to work on an example question.

The Electron Configuration: Condensed Example 1

Here it says to provide the condensed electron configuration for the aluminum atom. Atom means that we're dealing with the neutral form of it. If you look on the periodic table, step 1, we have to find the element on the periodic table. So aluminum has an atomic number of 13, which means it has 13 electrons involved. Step 2, we're going to locate the noble gas that comes before the element and place it inside brackets. So the noble gas before aluminum is neon, so put it in brackets. Step 3, continuing from the noble gas in brackets, complete the rest of the electron configuration. So we dealt with neon, so let's continue onward to aluminum. So next would come s32, and then p31. This would be the condensed electron configuration of aluminum. Instead of having to write 1s², 2s², 2p⁶, 3s², 3p¹, we have this new condensed electron configuration. Neon here is taking the spot of all of this. It's easier and faster for us to write the electron configuration of aluminum in this regard. So just remember, the condensed electron configuration saves us a lot of time in terms of writing out the electron arrangements for elements and ions.

Write the condensed electron configuration and electron orbital diagram for the following element:Zinc 

Here it says to write the condensed electron configuration and electron orbital diagram for the following element. We're looking at Zinc. Look on your periodic table, you'll see that Zinc has an atomic number of 30, which means that it has 30 electrons. So, we look for the noble gas that came before Zinc. If you look on the periodic table, you'll see that the element that came before Zinc was Argon. And then from there, we just continue onward. So after Argon, we're going to have \( 4s^2 \), and then, what, \( 3d \), count the slots, \( 10 \). So this would be the condensed electron configuration of Zinc. Here for the electron orbital diagram, you can write the noble gas, that takes care of all the electrons from \( 1s^2 \) all the way to \( 3p^6 \). Remember, the s sublevel has 1 orbital, and then the d sublevel has 5 orbitals. Remember in an orbital, one up, one down. Next, \( 3d^{10} \). All these electrons are in \( 3d \), so they're all the same type of orbital, so they all have the same energy. Following Hund's rule, you first half fill them. Up, up, up, up, up. Remember we have to fill in 10, so come back around, down, down, down, down, and down. So this will represent the electron orbital diagram for the zinc element.

Here’s what students ask on this topic:

What is the condensed electron configuration of iron (Fe)?

The condensed electron configuration of iron (Fe) starts with the noble gas preceding it, which is argon (Ar). Iron has an atomic number of 26. The configuration is written as [Ar] 3d⁶ 4s². This notation indicates that after the electron configuration of argon, iron has six electrons in the 3d subshell and two electrons in the 4s subshell.

How do you determine the noble gas to use in a condensed electron configuration?

To determine the noble gas to use in a condensed electron configuration, locate the element on the periodic table and identify the noble gas that comes immediately before it. Noble gases are found in Group 18 of the periodic table. For example, for an element like sulfur (S), which is in period 3, the preceding noble gas is neon (Ne). Therefore, the condensed electron configuration for sulfur would start with [Ne].

Why is the condensed electron configuration method preferred over the full ground state configuration?

The condensed electron configuration method is preferred because it simplifies the notation, making it quicker and easier to write. Instead of listing all the electron subshells from the beginning, it starts with the electron configuration of the last noble gas, which serves as a shorthand. This is particularly useful for elements with many electrons, as it reduces the complexity and length of the configuration.

What is the condensed electron configuration of the chloride ion (Cl^-)?

The chloride ion (Cl^-) has gained one electron compared to the neutral chlorine atom. Chlorine has an atomic number of 17, and its neutral condensed electron configuration is [Ne] 3s² 3p⁵. When it gains an electron to become Cl^-, the configuration becomes [Ne] 3s² 3p⁶, which is the same as the electron configuration of the noble gas argon (Ar).

How do you write the condensed electron configuration for transition metals?

To write the condensed electron configuration for transition metals, start with the noble gas preceding the element, then add the electrons in the 3d and 4s subshells. For example, for cobalt (Co), which has an atomic number of 27, the preceding noble gas is argon (Ar). The condensed electron configuration is [Ar] 3d⁷ 4s². Note that the 4s subshell is filled before the 3d subshell, but when writing the configuration, the 3d subshell is listed first.