The state of a substance at a given temperature can be predicted if its melting point and boiling point are known.
The melting point of oxygen is -218°C and its boiling point is -183°C. Predict the state of oxygen at -200°C.
Oxygen will be in the liquid state at -200°C (because this is between its melting and boiling points).
Particles in a substance have forces of attraction between them. When a substance in the solid state is heated:
The strength of the forces of attraction between particles varies between substances.
The stronger the forces of attraction between particles, the more energy is needed to overcome them, and so the higher the boiling point and the higher the melting point.