The electron cloud.
In insulators, electrons are tightly bound to their respective atoms, which makes it difficult for them to move freely within the material. This is because the energy required to detach the electrons from the atoms is high, preventing them from conducting electricity easily.
The forces of attraction between liquid atoms and liquid are more therefore they are close to another. This is what that keeps them close to each other.
Kinetic energy is possessed by moving atoms. It is the energy possessed by particles in motion.
Moving atoms have kinetic energy. This energy arises from their motion and is determined by their speed and mass.
All bonding between any types of atoms occurs in the electrons. All bonding is the result of electors: moving from one atom to another (ionic), being shared among 2+ atoms (covalent), or moving in a current-like fashion along multiple atoms (metallic).
The force holding an object is typically due to the interaction between molecules and atoms of the object's surface and the surface it is resting on. This force is known as static friction and prevents the object from moving when a force is applied to it.
A closed system is designed to keep additional atoms from entering or exiting. An insulated system prevents heat from entering or exiting.
Sodium is malleable because its metallic bonding allows its atoms to slide past one another easily, whereas sodium fluoride is not malleable because the strong ionic bonds between sodium and fluoride ions hold the compound in a rigid lattice structure. This lattice structure prevents the atoms from moving past each other, making sodium fluoride brittle instead of malleable.
The electrons in a penny are bound to the atoms within the penny's structure, which prevents them from flying out. The attractive force between the electrons and the positively charged nucleus of the atoms balances out the repulsive force between the electrons themselves. This equilibrium allows the electrons to move freely within the penny without escaping.
atoms? :P
Atoms are in constant motion. Even in a solid, the atoms are vibrating.
Temperature is a measure of how fast atoms in a material are moving. It reflects the average kinetic energy of the particles within the material. The higher the temperature, the faster the particles are moving.