Xenon
Atomic number 54 means that every Xenon nucleus contains 54 protons. That proton count is the element's identity: change it and you no longer have Xenon.
Start with the nucleus
Atomic number 54 means that every Xenon nucleus contains 54 protons. That proton count is the element's identity: change it and you no longer have Xenon.
Xenon (Xe) is chemical element 54. It belongs to the noble gases, and its reference state at room temperature is a gas. Those basic facts are a useful starting point for its chemistry and applications.
In practice, it turns up most often in lighting, medical imaging equipment and ion propulsion.
See the atom
Conceptual visual: electron shells are a learning aid, not a literal picture of quantum orbitals.
What this number means
Atomic number 54 means that every Xenon nucleus contains 54 protons. That proton count is the element's identity: change it and you no longer have Xenon.