How can chemists state with certainty that there will be no discovery of a new element between sulfur and chlorine?

1 Answer
Feb 20, 2018

Proton count/atomic numbers.

Explanation:

Sulfur has 16 protons, so its atomic number is 16. Chlorine has 17 protons, so its atomic number is 17. There cannot be a "new element" between the two because an atom cannot have 16.5 protons, and any atom with 16 protons must be a sulfur atom (because the 16 protons is what makes a sulfur atom a sulfur atom), and any atom with 17 protons must be a chlorine atom.