How do alkali metals react with nitrogen?

Alkali metals react with nitrogen to form nitrides, releasing a significant amount of energy in the process.

Alkali metals, which are found in Group 1 of the Periodic Table, are known for their high reactivity. This is due to their single electron in the outermost shell, which they are eager to lose in order to achieve a stable electron configuration. Nitrogen, on the other hand, is a non-metal that is keen to gain electrons to complete its outer shell. When alkali metals and nitrogen come into contact, they react to form nitrides.

The general equation for this reaction is 6M + N2 → 2M3N, where M represents an alkali metal and N represents nitrogen. For example, when lithium (Li) reacts with nitrogen, lithium nitride (Li3N) is formed. This reaction is highly exothermic, meaning it releases a significant amount of energy in the form of heat and light. This is why alkali metals are stored under oil, to prevent them from reacting with the nitrogen in the air.

The nitrides formed in these reactions are typically ionic compounds, with the alkali metal forming a positive ion (cation) and the nitrogen forming a negative ion (anion). These ions are held together by strong electrostatic forces of attraction, resulting in a stable compound.

It's important to note that not all alkali metals react with nitrogen in the same way. For instance, sodium (Na) reacts with nitrogen less readily than lithium. This is because sodium atoms are larger and have more electron shells, making it harder for the outermost electron to be lost. As a result, the reaction between sodium and nitrogen is slower and less exothermic than the reaction between lithium and nitrogen.