The Electron Configuration: Condensed: Videos & Practice Problems

Condensed electron configuration is an efficient method for representing the electron arrangements of elements or ions. This approach begins with the last noble gas preceding the element in question, allowing for a more streamlined notation. Understanding the layout of the periodic table is crucial, as it is divided into blocks: the s block starts with 1s, followed by the p block, d block, and f block.

To determine the condensed electron configuration, first identify the element and the noble gas that comes before it. This method is preferred for writing electron configurations, as it simplifies the process significantly. Unless specified otherwise, such as in the case of a full ground state electron configuration, the condensed form is typically the expected format.

For example, if you were to find the electron configuration for an element like chlorine (Cl), you would start with the noble gas neon (Ne), leading to the configuration: [Ne] 3s² 3p⁵. This notation effectively communicates the arrangement of electrons in a concise manner, making it a valuable tool in chemistry.

To determine the condensed electron configuration for an aluminum atom, which is neutral and has an atomic number of 13, we follow a systematic approach. First, we identify aluminum on the periodic table, confirming it has 13 electrons.

Next, we locate the nearest noble gas preceding aluminum, which is neon (Ne). We place neon in brackets to represent the electron configuration of the filled inner shells. This step simplifies our notation significantly.

Continuing from neon, we complete the electron configuration for aluminum. After neon, the next electrons fill the 3s and 3p orbitals. Thus, the configuration becomes:

[Ne] 3s^2 3p^1

This condensed electron configuration effectively replaces the longer form of writing out all the filled orbitals, which would be 1s² 2s² 2p⁶ 3s² 3p¹. By using the condensed form, we save time and effort while accurately representing the electron arrangement of aluminum.

In summary, the condensed electron configuration is a practical method for expressing the arrangement of electrons in an atom, particularly for elements with more complex configurations.