Answer:
Explanation: Mendeleev arranged the elements on the basis of their atomic mass. Melting and boiling point were used as the physical characteristics in deciding the position of elements. He arranged the elements and wrote the formula of their oxides and hydrides which seemed to possess same chemical formula.
Explanation:
What is the percent by mass of sodium in Na2SO4? total mass of element in compound molar mass of compound Use %Element x 100
Answer:
+3
Explanation:
The oxygen all have a -2 oxidation state. (peroxides are exceptions)
The chemical structure is symmetrical. Both carbon are equivalent.
2 (oxidation state of carbon) + 4 (oxidation state of oxygen) = charge of ion.
2 (oxidation state of carbon) + 4 (-2) = -2
oxidation state of carbon = +3
