Answer to Question #261834 in Inorganic Chemistry for RObert

Question

The made up element Imaginarium (Im) has an atomic number of 119. Im has been imagined to exist in 

three isotopic forms shown in the table below. 

 

Im isotope Isotopic mass (kg)

291Im  4.871 X 10-25 

302Im  5.055 X 10-25 

319Im  5.340 X 10-25 

Rank the Im isotopes from least to most stable and explain your reasoning

Answer 1

319Im 5.340 X 10-25 , 302Im 5.055 X 10-25 , 291Im 4.871 X 10-25

Elements with atomic number (Z) greater than 82 have no stable isotopes. Isotopes of elements with atomic number (Z) less than 20 and with a neutron to proton ratio of close to 1 are more likely to be stable if the nucleus contains an even number of protons and an even number of neutrons.