When solid materials are heated. the heat absorbed/added to the materials caused the materials to change its form

Complete question is;

When solid materials are heated.the heat absorbed/added to the materials caused the materials to change its form from?

From solid to liquid

Explanation:

When we heat solid materials, the heat causes the forces of attraction between the molecules to become weaker and as such, the material becomes more loose than it was in the solid state. As a result, the material now becomes a liquid because the molecules now have lesser forces of attraction and are a bit loose.

it means there are 3 atoms of oxygen