Question

How do compounds differ from their component elements?

Answer 1

The physical and chemical properties of a compound differ from its component elements. For example, the element sodium (Na) is a soft, silvery gray active metal that reacts explosively with water to form sodium hydroxide (`NaOH`) and hydrogen gas (`H_2`). The element chlorine, which exits as a diatomic gaseous molecule (`Cl_2`), has a green color and is toxic. These two elements react to form sodium chloride (`NaCl`), also called common table salt, which is a white crystalline solid that is not toxic and dissolves in water, but does not react with it.

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Figure 23: (a) Sodium metal (immersed in oil to prevent reaction with oxygen and moisture in the air); (b) chlorine gas; (c) the reaction between sodium and chlorine; (d) sodium chloride (common table salt)