Covalent Compounds
Definition and meaning of Covalent Compounds in chemistry.
Covalent compounds are chemical substances that are made entirely out of nonmetal atoms. These atoms share pairs of electrons instead of trading them completely away. This sharing process bonds the participating atoms together into distinct individual molecules.
In more detail
Atoms share their valence electrons so they can completely fill their outermost shells. This shared electron arrangement makes the bonded atoms much more chemically stable. Because they form distinct molecules, these compounds have very unique physical traits.
They usually have much lower melting and boiling points than solid ionic compounds. This explains why many covalent compounds exist as liquids or gases at room temperature. They also do not conduct electricity very well when in their pure solid states.
They cannot carry an electrical current because they lack free-floating ions or loose electrons. Sometimes the bonded atoms share the electrons perfectly evenly with each other. This perfectly even sharing creates a nonpolar compound like simple methane gas.
Other times, one stronger atom pulls the shared electrons much closer to its own nucleus. This unequal pulling creates a polar compound that features slightly charged opposite ends. Polar compounds often dissolve very easily in water because water is also highly polar.
A common student mistake involves misunderstanding what happens when you boil these compounds. Boiling only separates the whole independent molecules away from each other. The boiling process absolutely does not break the strong covalent bonds inside the molecules.
Key facts
| Field | General Chemistry |
|---|---|
| Typical elements | Two or more nonmetals |
| Structural unit | Distinct individual molecules |
| Melting points | Generally low compared to ionic compounds |
| Electrical conductivity | Very poor in pure solid or liquid states |
| Example formula | H2O |
Water (H2O) serves as a classic example of a polar covalent compound. One central oxygen atom shares pairs of electrons with two smaller hydrogen atoms. The stronger oxygen atom pulls the shared electrons much closer to its center. This unequal sharing gives the oxygen end a slight negative electrical charge. The two hydrogen atoms end up carrying a slight positive electrical charge instead. This specific polar shape lets liquid water dissolve many different important everyday chemicals.
Frequently asked questions
How do covalent compounds differ from ionic compounds?
Covalent compounds share electrons between nonmetals. Ionic compounds transfer electrons from a metal to a nonmetal. This full transfer creates charged ions.
Can covalent compounds conduct electricity?
Pure covalent compounds do not conduct electricity. They lack the free ions or mobile electrons needed to carry a current. However, some acids can conduct when dissolved in water.
Do covalent compounds have high or low melting points?
They usually have low melting points. You only need a little heat to push the separate molecules apart. You are absolutely not breaking the strong bonds inside the molecules.