A chemistry student was asked to calculate the number of moles of iron required to react with 1.20 mole of oxygen to produce iron(III)
oxide. His calculation is shown below:
I
1.20 mol 0, x 1 mol = 1.20 mol Fe
Is the student correct? Use evidence to support your answer.

i believe it is 40–40–20%

explanation:

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.