Thermodynamic stability and reaction spontaneity are important ideas in chemistry that work together. Let’s break them down into simpler parts.

1. Thermodynamic Stability: This just means how likely a system is to stay the same over time. A stable compound has low energy, so it doesn’t want to change into something else.

2. Gibbs Free Energy ($G$): This is a big part of understanding whether a reaction happens easily. A reaction is spontaneous if it lowers Gibbs free energy (that means $\Delta G < 0$). If the reaction makes a more stable product than what we started with, it will probably happen on its own.

3. Enthalpy and Entropy: These two things also play a role in whether a reaction is spontaneous. They are connected to changes in energy ($\Delta H$) and disorder ($\Delta S$). We can put this relationship in an equation:

   $\Delta G = \Delta H - T \Delta S$

   In this equation, temperature ($T$) is important. When the temperature goes up, it often helps reactions that increase disorder.

To sum it up, reactions that help a system become more stable (which means lower energy and more disorder) are usually spontaneous!