Naming Compounds. (phosphorus tetrachloride) Explain please?

Phosphorus does not have a charge of -3, it tends to form compounds where it takes 3 electrons from another atom where it gets this charge. However phosphorus or any nonmetal, on the right side of the periodic table, only takes electrons from metals, on the left side of the table. When phosphorus forms compounds with other nonmetals, such as chlorine, it forms covalent bonds and not ionic bonds. In these nonmetal-nonmetal compounds the Greek prefixes (mono, di, tri, tetra, penta, hexa, hepta, octa, nona, deca) are used to describe the number of atoms of each element in a molecule.