If an element has 8 valence electrons how many dots will be in the elements dot diagram

8 dots.

In the dot diagram the dots represent the valence electrons and each dot represents one valence electrons.

For example Ne has 8 valence electrons, so the dot representation is:

     **
 ** Ne **
     **

Because electrons have negligible mass, to account for the mass of the isotope, there must be 16 neutrons, 16 neutrally charged, massive, fundamental particles present in the sulfur nucleus. and thus finally, if we have the 32s2− ion, there are 18 electrons, 16 protons, and 16 neutrons.