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

Condensed electron configurations provide a streamlined method for representing electron arrangements in elements and ions. This approach begins with the last noble gas preceding the element in question, simplifying the notation. Understanding the periodic table's structure, including the s, p, d, and f blocks, is essential for determining the correct configuration. This method is preferred unless a full ground state electron configuration is specifically requested, making it a vital skill in chemistry.

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, we have our d block here, and we have 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. 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. 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, let's continue onward to aluminum. Next would come 3s², and then 3p¹. This is 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. So 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 4s2, 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 1s2 all the way to 3p6. Remember, the s sublevel has 1 orbital, and then the d sublevel has 5 orbitals. Remember in an orbital, 1 up, 1 down. Next, 3d10. 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, then 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). Therefore, the configuration is written as [Ar] 3d⁶ 4s². This notation indicates that iron has the same electron configuration as argon, plus the electrons in the 3d and 4s orbitals.

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), the noble gas preceding it is neon (Ne), so the condensed electron configuration 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 by starting with the last noble gas before the element. This reduces the length and complexity of the electron configuration, making it quicker and easier to write. It is especially useful for elements with many electrons, where writing out the full ground state configuration would be cumbersome.

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

The condensed electron configuration of a chloride ion (Cl^-) starts with the noble gas preceding chlorine, which is neon (Ne). Chlorine has an atomic number of 17, and when it gains an electron to become Cl^-, it has the same electron configuration as argon (Ar). Therefore, the configuration is [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 orbitals. For example, for copper (Cu), the noble gas is argon (Ar). The configuration is [Ar] 3d¹⁰ 4s¹. Note that transition metals often have exceptions to the typical filling order due to stability considerations.