Polonium
Atomic number 84 means that every Polonium nucleus contains 84 protons. That proton count is the element's identity: change it and you no longer have Polonium.
Start with the nucleus
Atomic number 84 means that every Polonium nucleus contains 84 protons. That proton count is the element's identity: change it and you no longer have Polonium.
Polonium (Po) is chemical element 84. It belongs to the post-transition metals, and its reference state at room temperature is a solid. Those basic facts are a useful starting point for its chemistry and applications.
In practice, it turns up most often in scientific research, nuclear heat and history.
See the atom
Conceptual visual: electron shells are a learning aid, not a literal picture of quantum orbitals.
What this number means
Atomic number 84 means that every Polonium nucleus contains 84 protons. That proton count is the element's identity: change it and you no longer have Polonium.