How to Write the Electron Configuration Using Arrows to Represent the Electrons

Write down the first shell of the electron configuration using standard chemical notation. The electron shells are labelled 1, 2, 3 and so forth. Each shell has a number of sub-shells, and the most common of these are labelled s, p and d. Each sub-shell can hold only a certain number of electrons. S sub-shells can hold 2 electrons, p sub-shells can hold 6 electrons, and d sub-shells can hold 10 electrons. For example, lithium has the atomic number 3, and therefore has three electrons. The configuration of the first shell is written as 1s2, which indicates there are two electrons in the 1s sub-shell.

Write down the complete electron configuration using standard chemical notation. Following the example, there is one more electron that needs to be placed, and the next sub-shell is the 2s. Therefore, the complete electron configuration is 1s2 2s1, which indicates there are two electrons in the 1s sub-shell and one electron in the 2s sub-shell.

Write down the electron configuration using arrows. Arrows that point up and down represent a property of electrons known as spin. Spin can be imagined to be a tiny magnetic field that electrons possess. The magnetic field can point either up or down. Electrons are added to shells in spin-up and spin-down pairs. Following the example, the chemical configuration of lithium can be written as the following: 1s UP DOWN 2s UP.

"UP" and "DOWN" represent up and down arrows, respectively.