Problema (soluciones porcentuales): 1.- Se requiere preparar 100g de una solución de NaOH al 19.9 % (en peso). ¿cuántos
gramos de NaOH y H2O se necesitan?​

he would use the colour black

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.