define properties of solid and liquid?
Answers
Answer:
In a solid, molecules are packed together, and it keeps its shape. Liquids take the shape of the container. Gases spread out to fill the container.
Answer: Solid is one of the three main states of matter, along with liquid and gas. Matter is the "stuff" of the universe, the atoms, molecules and ions that make up all physical substances. In a solid, these particles are packed closely together and are not free to move about within the substance. Molecular motion for the particles in a solid is confined to very small vibrations of the atoms around their fixed positions; therefore, solids have a fixed shape that is difficult to change. Solids also have a definite volume; that is, they keep their size no matter how you try to change them.
Solids are divided into two main categories, crystalline solids and amorphous solids, based on how the particles are arranged.
Crystalline solids
Crystalline solids, or crystals, are regarded as "true solids." Minerals are crystalline solids. Common table salt is one example of this kind of solid. In crystalline solids, the atoms, ions or molecules are arranged in an ordered and symmetrical pattern that is repeated over the entire crystal. The smallest repeating structure of a solid is called a unit cell, which is like a brick in a wall. Unit cells combine to form a network called a crystal lattice. There are 14 types of lattices, called Bravais lattices (named after Auguste Bravais, a 19th-century French physicist), and they are classified into seven crystal systems based on the arrangement of the atoms. The ChemWiki page at the University of California, Davis lists these systems as cubic, hexagonal, tetragonal, rhombohedral, orthorhombic, monoclinic and triclinic.
Aside from the regular arrangement of particles, crystalline solids have several other characteristic properties. They are generally incompressible, meaning they cannot be compressed into smaller shapes. Because of the repeating geometric structure of the crystal, all the bonds between the particles have equal strength. This means that a crystalline solid will have a distinct melting point, because applying heat will break all the bonds at the same time.
Crystalline solids also exhibit anisotropy. This means that properties such as refractive index (how much light bends when passing through the substance), conductivity (how well it conducts electricity) and tensile strength (the force required to break it apart) will vary depending on the direction from which a force is applied. Crystalline solids also exhibit cleavage; when broken apart, the pieces will have planed surfaces, or straight edges.
Types of crystalline solids
There are four types of crystalline solids: ionic solids, molecular solids, network covalent solids and metallic solids.
Ionic solids
Ionic compounds form crystals that are composed of oppositely charged ions: a positively charged cation and a negatively charged anion. Because of the strong attraction between opposite charges, it takes a lot of energy to overcome ionic bonds. This means that ionic compounds have very high melting points, often between 300 and 1,000 degrees Celsius (572 to 1,832 degrees Fahrenheit).
While the crystals themselves are hard, brittle and nonconductive, most ionic compounds can be dissolved in water, forming a solution of free ions that will conduct electricity. They may be simple binary salts like sodium chloride (NaCl), or table salt, where one atom of a metallic element (sodium) is bonded to one atom of a nonmetallic element (chlorine). They may also be composed of polyatomic ions such as NH4NO3 (ammonium nitrate). Polyatomic ions are groups of atoms that share electrons (called covalent bonding) and function in a compound as if they constituted a single charged ion.
