* Nitrogen's Natural State: Nitrogen in its elemental form has an atomic number of 7. This means it has 7 protons and 7 electrons. Its electronic configuration is 1s² 2s² 2p³. It has 5 valence electrons (the electrons in its outermost shell).
* Gaining Electrons: To achieve a stable octet (8 electrons in its outer shell) like the noble gases, nitrogen needs to gain 3 electrons.
* Formation of the Nitride Ion (N³⁻): When nitrogen gains 3 electrons, it becomes the nitride ion (N³⁻). This ion now has 10 electrons (7 original + 3 gained) and a negative charge due to the extra electrons.
Example: When magnesium (Mg) reacts with nitrogen (N₂), the following reaction occurs:
3 Mg + N₂ → Mg₃N₂
In this reaction, magnesium loses electrons to become a cation (Mg²⁺), and nitrogen gains electrons to become the nitride anion (N³⁻). The resulting compound is magnesium nitride (Mg₃N₂).
Important Note: Nitride ions are highly reactive and are not typically found in solution. They are more commonly found in solid compounds like magnesium nitride.
