Question

a polyatomic ion is named ammonium. what is the formula of this ion?

Explanation:

Step1: Recall ammonium ion formula

The ammonium ion is a common polyatomic ion. From chemical knowledge, the ammonium ion has the formula $\text{NH}_4^+$.

Step2: Confirm the formula

The ammonium ion is formed from ammonia ($\text{NH}_3$) accepting a proton ($\text{H}^+$), resulting in $\text{NH}_4^+$, with a +1 charge.

Answer:

$\boldsymbol{\text{NH}_4^+}$