Theo định nghĩa axit─bazơ của Bronstet, các chất và ion thuộc dãy nào dưới đây là trung tính? A. SO32-, Cl─ B. Na+, Cl─,
C. NH4+, HCO3-, CH3COO- D. HSO4-, NH4+, Na+

All the elements are arranged by melting points on the periodic table. in row they go from metals to gasses. in the row from sodium to argon, sodium is more reactive than the one on its right, magnesium.

Aphysical change is one that you can put in and remove like a ham sandwich. the stuff you put in there can be changem its not permanet. a chemical change is on that can't be change thats permanet. like when you make a cake and bake it. you can't get those ingredients back.