unsur 138The following table shows the atomic nuclei that are isotonic (same neutron number N = 81) and isobaric (same nucleon number A = 138) with Lanthanum-138. Naturally occurring isotopesUnsur 138, also known as Eka-Lawrencium, is a synthetic element with the atomic number 138. It was first predicted as part of the actinide series in the 1940s and was officially