1. Metallic Compounds (Alloys):
* Composition: These are made entirely of metal atoms.
* Examples: Bronze (copper and tin), brass (copper and zinc), steel (iron and carbon).
2. Nonmetallic Compounds:
* Composition: These are made entirely of nonmetal atoms.
* Examples: Carbon dioxide (CO₂), water (H₂O), nitrogen gas (N₂).
3. Ionic Compounds:
* Composition: These compounds are formed from the electrostatic attraction between metal and nonmetal atoms. Metals typically lose electrons to form positively charged ions (cations), while nonmetals gain electrons to form negatively charged ions (anions).
* Examples: Sodium chloride (NaCl), calcium oxide (CaO), potassium bromide (KBr).
4. Covalent Compounds:
* Composition: These compounds are formed by the sharing of electrons between nonmetal atoms.
* Examples: Methane (CH₄), carbon monoxide (CO), sulfur dioxide (SO₂).
Important Notes:
* Polyatomic Ions: Some covalent compounds form polyatomic ions, which act like single units in ionic compounds. Examples include the sulfate ion (SO₄²⁻) in calcium sulfate (CaSO₄).
* Exceptions: There are a few exceptions to these general rules. For example, some compounds containing both metals and nonmetals can be covalent, such as the metal carbonyl compounds (e.g., nickel carbonyl).
Let me know if you'd like to explore specific examples in more detail!
