What is the electron configuration for helium?

1 Answer
Jun 26, 2016

"He: " 1s^2

Explanation:

Helium, "He", has an atomic number equal to 2, which means that it has 2 protons in its nucleus.

A neutral helium atom will thus have 2 electrons surrounding its nucleus. This means that the electron configuration for helium has to account for only 2 electrons.

Both of these electrons are located on the first energy level, in the only subshell, and consequently only orbital available to them.

More specifically, both electrons will occupy the 1s orbital, the only orbital located in the s subshell.

The electron configuration will thus be

color(green)(|bar(ul(color(white)(a/a)color(black)("He: " 1s^2)color(white)(a/a)|)))

Here's how the electron configuration of helium looks compared with that of hydrogen, "H", which only has 1 electron surrounding its nucleus.

http://faculty.sdmiramar.edu/fgarces/zCourse/All_Year/Ch100_OL/aMy_FileLec/04OL_LecNotes_Ch100/03_AtomsElements/305_ElectronConfig/305_ElectronConfig.htmhttp://faculty.sdmiramar.edu/fgarces/zCourse/All_Year/Ch100_OL/aMy_FileLec/04OL_LecNotes_Ch100/03_AtomsElements/305_ElectronConfig/305_ElectronConfig.htm