# Come posso scrivere la formula per il nitruro di potassio?

La risposta corretta è K_3N.

To see how we arrived at that answer, we first have to examine the electronic configuration of K e N.

K ha 19 electrons and has the following electronic configuration rarr 1s^2 2s^2 2p^6 3s^2 3p^6 4s^1

As potassium obeys the octet rule, it will lose one electron in its 4s subshell to achieve a stable octet noble gas configuration, forming the ion, K^+.

Configurazione elettronica di K^+ rarr 1s^2 2s^2 2p^6 3s^2 3p^6

N has seven electrons and has the following electronic configuration rarr1s^2 2s^2 2p^3

Nitrogen also obeys the octet rule and will gain three electrons to achieve stable octet noble gas configuration, forming the negative nitride ion, N^-3.

Configurazione elettronica di N^-3rarr1s^2 2s^2 2p^6

Each nitrogen atom gains three electrons from three potassium atoms and each potassium atom loses one electron to a nitrogen atom. In this process each potassium atom becomes K^+ ion and each nitrogen atom N^-3 ione. The first 1:30 of questo video shows the movement of the electrons in potassium nitride (wordlessly).