The particles are still held together, but not rigidly, so they slide all over one another and prevent the material from having a definite shape
This description is referring to a liquid. Liquids have particles that are held together by intermolecular forces, but not in a rigid arrangement like solids. Instead, the particles are free to move past one another, allowing liquids to take on the shape of their container.
What you are describing is a characteristic of a state of matter known as a liquid. In a liquid, the particles (atoms, molecules, or ions) are still attracted to each other, but the forces between them are not strong enough to keep them in fixed positions. As a result, the particles are able to move past one another, leading to the ability of liquids to flow and take the shape of their container.
To understand this concept, let's delve into the behavior of particles at the atomic or molecular level. In a solid, the particles are closely packed and arranged in a regular, repeating pattern, which gives the solid its definite shape. The intermolecular forces in solids are strong enough to hold the particles in position, restricting their movement to vibrations around fixed points.
However, in a liquid, the intermolecular forces are weaker, and the particles have greater freedom of movement. Although the particles are still attracted to each other, these attractive forces are not sufficient to maintain a fixed arrangement. As a result, the particles in a liquid are able to slide past each other, allowing the liquid to flow and take the shape of its container.
It's important to note that the strength of intermolecular forces varies between different liquids. For example, liquids like water have relatively strong intermolecular forces, which is why even though they can flow, they still exhibit some resistance to deformation due to their stronger cohesion. On the other hand, liquids like alcohol or gasoline have weaker intermolecular forces, making them more volatile and easier to flow.
In summary, the ability of particles to slide all over one another in a liquid is what prevents it from having a definite shape. This behavior arises due to the comparatively weaker intermolecular forces, allowing the particles to move more freely while still being held together.