In general, Canada is a stable country.
the antonym of stable is unstable
Iraq is somewhere between stable and unstable. Iraqi Kurdistan in particular is rather stable with minimal insurgent activity. Central Iraq is more problematic. Iraq is not a developed country, but a developing country.
cuba is stable
stable
stable
Unstable.
The opposite of stable is unstable or variable.
Helium is a stable element.
Unstable
Selenium is generally considered stable in its elemental form. However, some of its isotopes are unstable and undergo radioactive decay.
Stable nuclei have a balanced number of protons and neutrons, while unstable nuclei have an imbalance. Unstable nuclei undergo radioactive decay to become more stable.