An unknown 50 gram piece of metal increased in temperature by 25 °C when 12000 J of heat was added. What is the specific heat of this mystery metal?

i'm assuming that the correct answer is indeed the first one/ "a"..

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.