Osmium has 5 stable isotopes and many more unstable isotopes, all having different atomic masses. See the related link below for a full table. Generally, its Atomic Mass no is taken as 190.23
Rhenium
Unified atomic mass unit
The atomic weight of carbon is approximately 12.01 atomic mass units.
Selenium (Se) has an atomic weight of 79,04.
The atomic weight of argon is approximately 39.95 atomic mass units.
Osmium is in the family of 'transition metals' in the periodic table.
Rhenium
Atomic weight = Weight of protons + Weight of neutrons
Unified atomic mass unit
Atomic Number = 6. Atomic Weight = 12.011
The atomic weight of carbon is approximately 12.01 atomic mass units.
The atomic weight of germanium is 72.63 atomic mass units.
85.4678 is the atomic weight of Rb.
Atomic weight 28.086
The atomic weight of zirconium is 91,224.
The atomic weight of zirconium is 91,224.
Selenium (Se) has an atomic weight of 79,04.