Ammonium (NH₄⁺) is not an element itself but rather a polyatomic ion composed of one nitrogen atom and four hydrogen atoms. It carries a positive charge of +1.
To calculate the atomic mass of ammonium, we need to sum up the atomic masses of its constituent atoms.
The atomic mass of nitrogen (N) is approximately 14.007 atomic mass units (amu), and the atomic mass of hydrogen (H) is approximately 1.00784 amu.
Atomic mass of ammonium (NH₄⁺) ≈ (1 nitrogen atom × 14.007 amu/atom) + (4 hydrogen atoms × 1.00784 amu/atom)
Atomic mass of ammonium ≈ 14.007 amu + 4.03136 amu
Atomic mass of ammonium ≈ 18.03836 amu
Therefore, the approximate atomic mass of ammonium (NH₄⁺) is approximately 18.03836 atomic mass units.