How long did it take humans to developed the Periodic Table? 1,000's of year
b
25 years
1,000,000 years
100 years
d

the answer is d : ) have a good da

your answer would be a. 12.5 kg

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.