Chapter 3- Atoms andMolecules Summary of Atoms andMolecules Law of conservation of mass: According to this law,during any physical or...

Chapter 4- Structure of Atom Summary ofStructure of Atom Ø Ø Atom is the smallest particle of an element. It has two parts: nucleus...

Chapter 12- Sound Introduction You have learnt that sound is a form of energy. It is produced by vibrations. Sound waves are...