Untriseptium
‘Untriseptium (IPA: /ʌntrʌɪˈsɛptiəm/) is a chemical element which has not yet been observed to occur naturally or be synthesised. Its atomic number is 137 and symbol is Uts. [.]
In a non-relativistic approximation, the speed of an electron in a 1s electron orbital, v, can be obtained using the expression:
v = Zac = Zc / 137.036
where Z is the atomic number, and α is the fine structure constant, a measure of the strength of electromagnetic interactions. Under this approximation, any element with an atomic number of greater than 137 would require 1s electrons to be traveling faster than c, the speed of light.’
