You're likely referring to the fact that carbon exists as a solid at room temperature, while nitrogen exists as a gas. This difference in states of matter arises primarily due to the differences in their intermolecular forces.

Here's a breakdown:

* Carbon: Carbon atoms form strong covalent bonds with each other, leading to the formation of large, complex structures like graphite and diamond. These structures are held together by strong covalent bonds, which require a lot of energy to break. Therefore, carbon has a high melting point and exists as a solid at room temperature.

* Nitrogen: Nitrogen atoms form a triple bond with each other to form a diatomic molecule (N₂). This triple bond is very strong, but the intermolecular forces between different nitrogen molecules are weak van der Waals forces. These forces are much weaker than the covalent bonds within the nitrogen molecule. As a result, nitrogen molecules can easily overcome these weak forces at room temperature, allowing it to exist as a gas.

In summary:

* Strong covalent bonds within the carbon structure lead to a solid state at room temperature.

* Weak intermolecular forces between nitrogen molecules allow it to exist as a gas at room temperature.

This difference in intermolecular forces is the key reason for the difference in states of matter between carbon and nitrogen at room temperature.