Final answer:
In the Lewis structure of the ammonium ion, a total of 8 valence electrons must be shown, which includes the 5 valence electrons from nitrogen, 4 from hydrogen, minus one electron for the ion's 1+ charge.
Step-by-step explanation:
The question asks how many electrons must be shown in the Lewis structure of the ammonium ion (NH4+). To find this number, we account for the valence electrons of the nitrogen atom and the hydrogen atoms and adjust for the charge of the ion. A nitrogen atom has 5 valence electrons, and each of the 4 hydrogen atoms contributes 1 valence electron, resulting in a total of 9. However, we also have to subtract one electron due to the 1+ charge of the ammonium ion. Therefore, the total number of electrons to be shown in the Lewis structure is 8.