The atomic mass of Iodine (I) is less than the atomic mass of Tellurium (Te). But an Iodine atom has one more proton than a Tellurium atom.How is this situation possible??

Answer 1

I has 53 protons and has an atomic mass of 126.9

Te has 52 protons and has an atomic mass of 127.6

This atomic mass is the sum of the number of protons + the number of neutrons.

I has 74 neutrons and Te has 76 neutrons, and this explain why the atomic mass of Te is greater than that for I.