Electron configuration

This notation is called the electron configuration of an element. It describes how the electrons are arranged in the energy levels (or shells) and orbitals of an atom.

The first number (1, 2, or 3) denotes the energy level or shell. The letter (s, p, d, or f) denotes the type of orbital within that shell. The number after the letter (2, 6, 4, etc.) denotes the number of electrons in that orbital.

In the case of sulfur (S), the electron configuration is:

1s2 - Two electrons in the 1s orbital (first energy level)

2s2 - Two electrons in the 2s orbital (second energy level)

2p6 - Six electrons in the 2p orbital (second energy level)

3s2 - Two electrons in the 3s orbital (third energy level) 3p4 - Four electrons in the 3p orbital (third energy level)

This means that sulfur has a total of 16 electrons, with two in the first energy level, eight in the second energy level, and six in the third energy level.