Copper II nitrate itself doesn't "burn" in the traditional sense, as it's an ionic compound and doesn't undergo combustion like organic materials. However, when heated strongly, it decomposes, producing a characteristic color change:

Copper II nitrate decomposes to produce a green flame due to the excitation of copper ions.

Here's what happens:

1. Decomposition: When heated, copper II nitrate (Cu(NO3)2) decomposes into copper oxide (CuO), nitrogen dioxide (NO2), and oxygen gas (O2).

2. Flame Production: The nitrogen dioxide gas produced is a reddish-brown gas. When it is heated further, it emits a bright green light.

Therefore, while copper II nitrate itself doesn't burn, its decomposition products, particularly nitrogen dioxide, can produce a green flame under high temperatures.