Question

What is the electron configuration for helium?

Answer 1

`"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.