General Chemistry Concepts (Grade 11)
1. Matter & Its Properties
Matter: anything that has mass and occupies space.
Two main classifications:
o Pure substances (elements, compounds).
o Mixtures (homogeneous – solutions; heterogeneous –
suspensions, colloids).
Physical properties: color, density, melting point.
Chemical properties: flammability, reactivity.
2. Atomic Structure
Atom = protons (+), neutrons (0), electrons (–).
Atomic number (Z) = number of protons.
Mass number (A) = protons + neutrons.
Isotopes: same Z, different A.
Electrons occupy energy levels (shells, orbitals).
3. Periodic Table
Arranged by increasing atomic number.
Groups (columns): similar properties (e.g., Group 1: alkali metals,
Group 17: halogens, Group 18: noble gases).
Periods (rows): properties gradually change across.
Trends:
o Atomic radius ↓ across a period, ↑ down a group.
o Ionization energy ↑ across, ↓ down.
o Electronegativity ↑ across, ↓ down.
4. Chemical Bonding
Ionic bonds: transfer of electrons (metal + nonmetal).
Covalent bonds: sharing of electrons (nonmetal + nonmetal).
Metallic bonds: “sea of electrons” in metals.
Shapes predicted by VSEPR Theory (linear, bent, trigonal planar,
tetrahedral, etc.).
5. Stoichiometry
Based on balanced chemical equations.
Mole (mol): 1 mol = 6.022 × 10²³ particles (Avogadro’s number).
Molar mass: mass of 1 mol of substance (g/mol).
Conversions:
o Mass ↔ Moles ↔ Particles ↔ Volume (at STP, 1 mol gas = 22.4 L).
6. States of Matter & Gas Laws
Solids (definite shape & volume), Liquids (definite volume), Gases (no
definite shape or volume).
Gas Laws:
o Boyle’s Law: P₁V₁ = P₂V₂ (at constant T).
o Charles’ Law: V₁/T₁ = V₂/T₂ (at constant P).
o Gay-Lussac’s Law: P₁/T₁ = P₂/T₂ (at constant V).
o Combined Gas Law: P₁V₁/T₁ = P₂V₂/T₂.
o Ideal Gas Law: PV = nRT.
7. Thermochemistry
Energy changes in reactions.
Exothermic = releases heat (–ΔH).
Endothermic = absorbs heat (+ΔH).
Law of Conservation of Energy: Energy is not created or destroyed.
8. Solutions & Concentrations
Concentration units:
o Molarity (M) = moles solute / liters solution.
o Mass percent = (mass solute / mass solution) × 100.
Solubility depends on temperature, pressure, and nature of
solute/solvent.
“Like dissolves like” (polar dissolves polar, nonpolar dissolves
nonpolar).
9. Acids & Bases
Acid: proton donor (H⁺), Base: proton acceptor (OH⁻).
pH scale: 0–6 acidic, 7 neutral, 8–14 basic.
Strong vs. Weak acids/bases differ in ionization.
Neutralization: acid + base → salt + water.
10. Redox Reactions & Electrochemistry
Oxidation = loss of electrons, Reduction = gain of electrons.
OIL RIG (Oxidation Is Loss, Reduction Is Gain).
Occurs in batteries, corrosion, electrolysis.
