Air
* Nitrogen (N2): The most abundant gas in air, making up about 78%. Nitrogen molecules are made of two nitrogen atoms bonded together.
* Oxygen (O2): The second most abundant gas, making up about 21%. Oxygen molecules are made of two oxygen atoms bonded together.
* Argon (Ar): A noble gas, making up about 0.9% of air. Argon atoms are single atoms.
* Carbon Dioxide (CO2): A trace gas, but crucial for the greenhouse effect. Carbon dioxide molecules are made of one carbon atom bonded to two oxygen atoms.
* Other Gases: Trace amounts of other gases like neon, helium, methane, and krypton are also present.
Water
* Hydrogen (H): Water molecules are made of two hydrogen atoms bonded to one oxygen atom.
* Oxygen (O): See above.
Metals
* Metal Atoms: Metals are made of a lattice of metal atoms arranged in a repeating, crystalline structure. The atoms are held together by metallic bonds, which are a type of chemical bond that involves the sharing of electrons between many atoms.
* Examples:
* Iron (Fe): Iron atoms are arranged in a body-centered cubic lattice.
* Gold (Au): Gold atoms are arranged in a face-centered cubic lattice.
* Copper (Cu): Copper atoms are arranged in a face-centered cubic lattice.
Key Points:
* Elements vs. Molecules: Some of these substances are made of elements (like nitrogen or argon) which are single types of atoms. Others are made of molecules (like oxygen or carbon dioxide) which are two or more atoms bonded together.
* States of Matter: The particles in air are far apart and move freely (gas). The particles in water are closer together and move less freely (liquid). The particles in metals are tightly packed and have a fixed shape (solid).
Let me know if you'd like more details on any of these substances!
