1. Matter in Our Surroundings (Hamare Aas-Paas ke Padarth)

Simple Concept: Har wo cheez jiska vajan (mass) ho aur jo jagah gherati ho, wo Matter hai.

States of Matter:

Solid: Fixed shape aur volume (e.g., Pathar).

Liquid: Fixed volume lekin shape nahi (e.g., Pani).

Gas: Na fixed shape, na volume (e.g., Hawa).

Change of State:

Melting: Solid se Liquid banna.

Boiling: Liquid se Gas banna.

Sublimation: Solid ka seedha Gas banna (e.g., Camphor/Kapoor).

Evaporation: Liquid ka gas mein badalna boiling point se kam temperature par. Isse Cooling hoti hai.

2. Is Matter Around Us Pure? (Kya Hamare Aas-Paas ke Padarth Shuddh Hain?)

Pure Substances: Jo sirf ek hi tarah ke particles se bane hon (Elements aur Compounds).

Mixtures: Jab do ya do se zyada chizen bas mix hon, judi na hon.

Homogeneous: Ek jaisa dikhne wala (e.g., Namak aur Pani).

Heterogeneous: Alag-alag dikhne wala (e.g., Ret aur Pani).

Solutions:

Saturated Solution: Jisme aur zyada solute na ghul sake.

Colloids: Jo dikhne mein homogeneous lagte hain par hote heterogeneous hain (e.g., Doodh).

Separation Techniques: Chromatography, Distillation, aur Crystallization.

3. Atoms and Molecules (Parmanu aur Anu)

Laws of Chemical Combination:

Law of Conservation of Mass: Mass na banta hai na khatm hota hai.

Law of Constant Proportions: Ek compound mein elements hamesha fixed ratio mein hote hain.

Atom: Matter ki sabse choti unit.

Molecule: Do ya do se zyada atoms ka group.

Valency: Kisi element ki combine hone ki kshamta.

Mole Concept: 1 Mole = $6.022 \times 10^{23}$ particles (Avogadro Number).

4. Structure of the Atom (Parmanu ki Sanrachna)

Sub-atomic Particles:

Protons (+): Nucleus ke andar hote hain.

Neutrons (Neutral): Nucleus ke andar hote hain.

Electrons (-): Nucleus ke bahar chakkar lagate hain.

Atomic Models: Thomson ka "Plum Pudding", Rutherford ka "Gold Foil Experiment", aur Bohr ka "Energy Shells" model.

Atomic Number (Z): Protons ki sankhya.

Mass Number (A): Protons + Neutrons.

Isotopes: Ek hi element jinka atomic number same ho par mass alag (e.g., Carbon-12 aur Carbon-14).