Which of the following equations is balanced? a) HgO -> Hg + 02
b) 2Mg + C12 --> MgCl2
c) P4 + 402 - 2P205
d) 2AgNO3 + CaCl2 --> 2AgCl + Ca(NO3)2
e) None of the above​

a

Explanation:

a because a

ok whats the question if not i cannot you i need question and need a thing to answer

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.