硝酸铵是一种氮肥，化学式NH4NO3，其铵根中的氮元素的化合价为（ ） A. -3 B. +1 C. +4 D. +5

硝酸铵是一种氮肥，化学式NH4NO3，其铵根中的氮元素的化合价为（ ） A. -3 B. +1 C. +4 D. +5

To determine the化合价 of nitrogen in the ammonium ion (NH₄⁺), we use the principle that the sum of valence charges in an ion equals its overall charge. The ammonium ion has a charge of +1, and hydrogen typically has a valence of +1 in such compounds. Let the valence of nitrogen be $x$. For NH₄⁺:

$x + 4(+1) = +1$

Solving for $x$:
\(x + 4 = 1\)
\(x = 1 - 4 = -3\)

Answer: A