# NH_4C_2H_3O_2, is made of how many elements?

An element is simply a particular species of atom with one particular atomic number assigned to it. Some examples are ${\text{N}}_{2}$ (nitrogen), $\text{Sb}$ (antimony), ${\text{I}}_{2}$ (iodine), $\text{Bi}$ (bismuth), etc.
${\text{NH"_4"C"_2"H"_3"O}}_{2}$