Regarding the type of connection
As for the type of binding, the substances are classified as ionic, molecular or metallic. The substances ionic have at least one ionic bond.
Example: NaCl (sodium chloride)
NaNO2 (sodium nitrite)
Ionic substances have high boiling and melting points; many of them, when dissolved in water, have their ions separated by water in a process called ion dissociation; conduct electric current in aqueous solution.
See the table for other examples of ionic substances:
X-ray used in gastrointestinal tract
The substances molecular they are formed exclusively by covalent bonds. In general, it has a low boiling and melting temperature. Most of them do not conduct electricity in aqueous solution. They form molecules.
Examples: water (H2O)
See the table for other examples of molecular substances:
Poison gas from incomplete combustion of gasoline and alcohol
Product of combustion reaction. Absorbed by plants for use in photosynthesis
Alcohol & Fuel Ingredient
The substances metallic they are formed exclusively by metallic connections.
Examples: Iron (Fe), Silver (Ag), Gold (Au), Aluminum (Al).
Regarding the number of chemical elements
As for the number of chemical elements, the substances can be classified as simple or compound.
Simple substance is one formed by a single chemical element. Examples:
Iron (Fe), Aluminum (Al), Hydrogen gas (H2).
Simple Substance - Iron
Composite substance is one formed by more than one type of chemical element. Examples:
Sodium Chloride (NaCl), Carbon Monoxide (CO), Water (H2O).
Composite Substance - NaCl