Final answer:
Nitrogen's state of matter at -220°C is a solid.
Step-by-step explanation:
Nitrogen's state of matter at -220°C would be a solid. This is because the melting point of nitrogen is -210.0°C, which means that at temperatures below -210.0°C, nitrogen exists in a solid state. Therefore, at -220°C, which is lower than the melting point, nitrogen would be in a solid state.