The bottom number on the periodic table is called?

The atomic number that should be here, 57, is located at the bottom of the table in the row called the Lanthanides. Directly below the space in Row 6, in Row 7, is another empty space, which is filled by a row called the Actinides, also seen at the bottom of the chart.

Explanation:

hope this helps!

answer; economic order quantity;

if you mean hydrogen and oxygen then water is the product