Here's why:

* Electron Configuration: Sulfur's electron configuration is 1s² 2s² 2p⁶ 3s² 3p⁴.

* Valence Shell: The valence shell is the outermost shell of an atom, which in sulfur's case is the 3rd shell.

* Valence Electrons: The electrons in the valence shell are called valence electrons, and they are the ones involved in chemical bonding. Sulfur has 2 electrons in the 3s subshell and 4 electrons in the 3p subshell, making a total of 6 valence electrons.