Final answer:
The original properties of uncombined elements are not present in compounds. Chemical combination alters these properties significantly, resulting in compounds with unique chemical and physical properties that can be vastly different from those of the constituent elements.
Step-by-step explanation:
The properties of uncombined elements are not present in compounds. When elements chemically combine to form compounds, they exhibit entirely different properties. For instance, sodium is a soft, shiny metal, and chlorine is a yellow-green gas, but combined, they form the white, crystalline compound sodium chloride (table salt). This illustrates how the distinctive characteristics of elements change upon chemical combination.
Each compound has a unique set of chemical and physical properties that are usually vastly different from the properties of their constituent elements. For example, hydrogen and oxygen are both gases that support combustion, yet when combined, they form water, a liquid that extinguishes fire. Thus, one cannot assume the properties of elements are retained in compounds.
In essence, when elements react and form compounds, they obey specific stoichiometric ratios, witnessed in their chemical formulas, which does not preserve their original elemental properties.