Why is atomic number better than atomic mass for organizing the elements in the periodic table?

How many liters of oxygen gas, at standard temperature and pressure, will react with 35.8 grams of iron metal? 4 fe (s) + 3 o₂ (g) → 2 fe₂o₃ (s)

Determine the reaction and balance the following equations urgent due in the morning

Write the chemical formula for a compound that is made of an element from group 1 and an element from group 17