How many valence electrons are in an atom of sulfur?

Jun 17, 2014

$6$

Explanation:

Sulfur has six valence electrons.

Valence electrons are the outermost electrons which, therefore, are located on the highest energy levels. Consequently, these are the electrons available for chemical bonding.

To determine the valence number, look at electron configurations which denote the number of electrons in the different energy levels and orbitals.

Neutral sulfur has 16 electrons because its atomic number is 16.

The electron configuration is $\text{ } 1 {s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{2} 3 {p}^{4}$

What does this configuration tell us?

Sulfur has two electrons in the $1 s$ orbital, two electrons in the $2 s$ orbital, and six electrons in the $2 p$ orbitals. These electrons are part of the first and second energy levels, the electron core.

The next energy level, the last one, is the outermost energy which comprises the valence shell. There are two electrons in the $3 s$ orbital and four electrons in the $3 p$ orbitals. Add the electrons to these last types of orbitals and you have the number of valence electrons.