Core concepts
- Matter classification: element, compound, mixture.
- Homogeneous vs heterogeneous mixtures.
- Symbols, valency and simple formula writing.
- Balancing basic chemical equations.
Quick strategy
- Identify atom type and count first.
- Apply valency method for formula.
- Balance atoms one element at a time.
Common mistakes
- Confusing mixture with compound.
- Writing molecular formula directly from names without valency check.