Untriseptium

Untriseptium (), also called eka-dubnium or element 137, is a possible chemical element which has not been synthesized. Due to instabilities, it is not known if this element is possible, as the instabilities may hint that the periodic table ends soon after the island of stability at unbihexium. Its atomic number is 137 and symbol is Uts.

The name untriseptium is a temporary name.

 Importance 
It is sometimes called feynmanium (symbol Fy) because Richard Feynman noted that a simplistic interpretation of the relativistic Dirac equation runs into problems with electron orbitals at Z > 1/α = 137, suggesting that neutral atoms cannot exist beyond untriseptium, and that a periodic table of elements based on electron orbitals breaks down at this point. However, a more thorough analysis calculates the limit to be around element 173., and references therein.

 Electronically unstable  1s orbit 
Untriseptium has a theoretically impossible electron velocity for the 1s orbital's electrons. This is because when this speed calculated by the formula stated by Bohr's model returns a speed higher than the speed of light and hence is theoretically unviable leading a another reason why it is believed to be the end of the periodic table.

 Related pages 

 Dubnium
 Atomic orbital
 Untrioctium
 Unennunium

 References 

Category:Hypothetical chemical elements