Last Updated: November 21, 2025
Common Elements
| Symbol | Name | Atomic Number |
|---|---|---|
H
|
Hydrogen | 1 |
C
|
Carbon | 6 |
N
|
Nitrogen | 7 |
O
|
Oxygen | 8 |
Na
|
Sodium | 11 |
Cl
|
Chlorine | 17 |
Fe
|
Iron | 26 |
Au
|
Gold | 79 |
Chemical Formulas
| Compound | Formula |
|---|---|
Water
|
H₂O |
Carbon Dioxide
|
CO₂ |
Salt (Sodium Chloride)
|
NaCl |
Ammonia
|
NH₃ |
Glucose
|
C₆H₁₂O₆ |
Sulfuric Acid
|
H₂SO₄ |
Key Concepts
pH Scale
0-6 acidic, 7 neutral, 8-14 basic
Molar Mass
Sum of atomic masses in a molecule
Avogadro's Number
6.022 × 10²³ particles/mole
💡 Pro Tip:
Balance chemical equations: same number of atoms on both sides!