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Chapter 1: Fundamentals of Chemistry
Introduction to Chemistry
Chemistry is the branch of science that deals with the composition, structure, properties, and reactions of matter. It is often called the "central science" because it connects physics, biology, and other sciences.
States of Matter
- Solid: Definite shape and volume, particles closely packed
- Liquid: Definite volume but no definite shape
- Gas: No definite shape or volume
- Plasma: Ionized gas (found in stars)
Elements, Compounds, and Mixtures
- Element: Pure substance made of one type of atom (e.g., Fe, O₂)
- Compound: Pure substance made of two or more elements chemically combined (e.g., H₂O)
- Mixture: Two or more substances physically combined (e.g., salt water)
Types of Mixtures
- Homogeneous: Uniform composition (e.g., alloys, solutions)
- Heterogeneous: Non-uniform composition (e.g., sand in water)
Chapter 2: Structure of Atom
Discovery of Sub-atomic Particles
- Electron (e⁻): Discovered by J.J. Thomson (1897) - negatively charged
- Proton (p⁺): Discovered by Rutherford (1919) - positively charged
- Neutron (n⁰): Discovered by Chadwick (1932) - no charge
Atomic Models
Thomson's Model (1898)
Atom is a sphere of positive charge with electrons embedded in it (like plum pudding).
Rutherford's Model (1911)
Atom has a dense positive nucleus with electrons orbiting around it. Most of the atom is empty space.
Bohr's Model (1913)
Electrons revolve in fixed circular orbits (energy levels) without radiating energy.
Electronic Configuration
Distribution of electrons in energy levels:
Maximum electrons in shell n = 2n²
K-shell (n=1): 2 electrons
L-shell (n=2): 8 electrons
M-shell (n=3): 18 electrons
N-shell (n=4): 32 electrons
Valence Electrons
Electrons in the outermost shell determine chemical properties. Maximum valence electrons = 8.
Chapter 3: Periodic Table
History
Elements arranged by atomic number (Moseley) or atomic mass (Mendeleev).
Modern Periodic Law
"Properties of elements are periodic function of their atomic numbers."
Groups and Periods
- Groups (18): Vertical columns - elements with similar properties
- Periods (7): Horizontal rows - elements with same shell number
Important Groups
- Group 1: Alkali Metals (Li, Na, K, Rb, Cs, Fr)
- Group 2: Alkaline Earth Metals (Be, Mg, Ca, Sr, Ba, Ra)
- Group 17: Halogens (F, Cl, Br, I, At)
- Group 18: Noble Gases (He, Ne, Ar, Kr, Xe, Rn)
Trend Across Period
- Atomic size: Decreases →
- Ionization energy: Increases →
- Electronegativity: Increases →
- Metallic character: Decreases →
Chapter 4: Chemical Bonding
Types of Chemical Bonds
1. Ionic Bond
Transfer of electrons from metal to non-metal.
Na → Na⁺ + e⁻
Cl + e⁻ → Cl⁻
Na⁺ + Cl⁻ → NaCl
2. Covalent Bond
Sharing of electrons between non-metals.
H₂: H• + •H → H:H
O₂: O::O
N₂: N≡N
3. Metallic Bond
Sea of electrons moving freely between metal atoms.
Electronegativity Difference
- < 0.4: Non-polar covalent
- 0.4 - 1.7: Polar covalent
- > 1.7: Ionic
Chapter 5: Physical States of Matter
Boyle's Law
P₁V₁ = P₂V₂ (at constant T)
Charles's Law
V₁/T₁ = V₂/T₂ (at constant P)
Ideal Gas Equation
PV = nRT
R = 8.314 J/mol·K (Gas constant)
Avogadro's Law
V₁/n₁ = V₂/n₂ (at constant T, P)
Chapter 6: Solutions
Types of Solutions
- Solute: Substance dissolved (less quantity)
- Solvent: Substance doing dissolving (more quantity)
Concentration Units
Mass % = (Mass of Solute / Mass of Solution) × 100
Molarity (M) = Moles of Solute / Volume (L)
Solubility
Maximum amount of solute dissolved in 100g solvent at given temperature.
Factors affecting solubility:
• Temperature (↑ T = ↑ solubility for solids)
• Temperature (↑ T = ↓ solubility for gases)
• Pressure (↑ P = ↑ solubility for gases)
Chapter 7: Electrochemistry
Electrolytes
- Strong Electrolytes: Complete dissociation (NaCl, HCl)
- Weak Electrolytes: Partial dissociation (CH₃COOH)
Faraday's Laws of Electrolysis
m = Z × I × t
Where: m = mass deposited, Z = electrochemical equivalent, I = current, t = time
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