Which scientist arranged the elements in order of increasing atomic number, rather than increasing atomic mass? antoine lavoisier dmitri mendeleev henry moseley john newlands

The answer is: Henry Moseley.

Henry Gwyn Jeffreys Moseley (1887–1915) proposed that the number of positive nuclear charges (protons) in atom is equal to its atomic number in the periodic table.

Mendeleev did not know about isotopes and he arranged the elements in order of increasing relative atomic mass.

For example, positions of iodine and tellurium were reversed in Mendeleev's table, because of different isotopes, but Moseley solved anomalies like this one.

2h2o2--> 2h2o + o2

this reaction is of the spontaneous decomposition of hydrogen peroxide down into water and oxygen.

add 2 molecules of hydrogen peroxide and 2 molecules of water. since oxygen is naturally diatomic, the total number of atoms of each element is now the same on both sides of the equation so it is balanced.

this may not be entirely correct but let me know.