What is the electron configuration for helium?

1 Answer
Jun 26, 2016

Answer:

#"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.htm