The masses of a potassium-40 atom, a proton and a neutron are 39.963999 amu, 1.007825 amu and 1.008665 amu, respectively. Calculate to four significant figures the mass defect in amu and the energy released in MeV/nucleon, in the formation ofK1940from the appropriate number of protons and neutrons.

answer: atomic mass was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.

explanation:

originally atomic mass was used to arrange elements on the periodic table from left to right in a row. each column then shows similar properties of elements of a group.

in modern periodic table, the atoms are arranged in increasing atomic number. as atomic number represents the number of protons in an atom which is unique for every atom.