How many grams of hydrogen gas will be required to react with 17.5 g of oxygen gas to make water? Write and balance the synthesis reaction

Copper, silver, aluminum, cobalt, chromium, mercury 

Hello thereone of the following properties was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version. which property fits this description? answer: atomic mass  was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.

Answers are 1,2,4 its correct on edgenuity.