how many elements in (NH4)2SO4

Answer 1

4.
N, H, S, O

Answer 2

thank you
so is AL2O3 3 elements
Ca(HCO3)2 4 elements

Answer 3

Ca(HCO3)2 is 4, right.
Al2O3 is 2; i.e., Al and O

Answer 4

Thank you

Answer 5

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