HOW MANY GRAMS OF CAC2 ARE NEEDED TO REACT COMPLETELY WITH 490 MOLES H2O

a:

by the combination of an unlimited number of elements

there is none because earth is stationary and flat.

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.