Grade 11
  1. Basic concepts of chemistry  1.1. Importance of Chemistry  1.2. Nature and scope of chemistry  1.3. laws of chemical combination  1.3.1. Law of conservation of mass  1.3.2. Law of definite proportions  1.3.3. Law of multiple proportions  1.3.4. Law of gaseous volume  1.3.5. Avogadro's Law  1.4. Dalton's atomic theory  1.5. Mole concept and molar mass  1.6. Percent composition  1.7. Empirical and molecular formula  1.8. Stoichiometry and Stoichiometric Calculations  1.9. Limiting reagent concept
  2. Structure of the atom  2.1. Discovery of the electron, proton, and neutron  2.2. Atomic Model  2.2.1. Thomson's model  2.2.2. Rutherford's model  2.2.3. Bohr's model  2.3. Quantum mechanical model of the atom  2.4. Dual nature of matter and radiation  2.5. Heisenberg's uncertainty principle  2.6. Quantum numbers  2.7. Atomic orbitals and their shapes  2.8. Electronic configuration of elements  2.9. Aufbau principle  2.10. Pauli's exclusion principle  2.11. Hund's maximum multiplicity rule  2.12. de Broglie's hypothesis  2.13. Photoelectric effect
  3. Classification of elements and periodicity in properties  3.1. Historical development of the periodic table  3.2. Modern Periodic Law and Periodic Table  3.3. Periodic trends in properties  3.3.1. Atomic and Ionic Radius  3.3.2. Ionization enthalpy  3.3.3. Electron gain enthalpy  3.3.4. Electronegativity  3.3.5. Valency  3.3.6. Metallic and Non-Metallic Properties  3.3.7. Oxidation states  3.4. Unusual Properties of the First Elements
  4. Chemical Bonding and Molecular Structure  4.1. Kossel–Lewis approach to chemical bonding  4.2. Ionic or electrovalent bond  4.3. Covalent bond and its features  4.4. Bond parameters  4.5. VSEPR Theory  4.6. Valence bond theory  4.7. Hybridization and its types  4.8. Molecular orbital theory  4.8.1. Bond order and stability  4.9. Hydrogen bonding
  5. States of matter  5.1. Intermolecular forces  5.2. Gas Laws  5.2.1. Boyle's law  5.2.2. Charles's Law  5.2.3. Avogadro's Law  5.2.4. Dalton's law of partial pressure  5.2.5. Graham's law of spread  5.3. Ideal Gas Equation and Applications  5.4. Real gases and deviations from ideal behaviour  5.5. Kinetic molecular theory of gases  5.6. Liquefaction of gases  5.7. Properties of Liquids  5.8. Surface tension and viscosity
  6. Thermodynamics  6.1. System and environment  6.2. Types of systems in thermodynamics  6.3. Types of procedures  6.4. First law of thermodynamics  6.5. Internal energy and enthalpy  6.6. Heat capacity and specific heat  6.7. Hess's law of constant heat summation  6.8. Bond dissociation enthalpy  6.9. Enthalpy of formation and combustion  6.10. Enthalpy of solution and neutralization  6.11. Spontaneity and the second law of thermodynamics  6.12. Gibbs free energy and its applications
  7. Balance  7.1. The concept of balance  7.2. Equilibrium constant and its applications  7.3. Le Chatelier's principle  7.4. Ionic equilibrium in solutions  7.5. Acid and Base Theory  7.5.1. Arrhenius concept  7.5.2. Bronsted-Lowry concept  7.5.3. Lewis concept  7.6. pH Scale and pOH  7.7. Common ion effect  7.8. Hydrolysis of salts  7.9. Buffer solutions and their mechanism of action  7.10. Solubility equilibrium of sparingly soluble salts
  8. Redox reactions  8.1. Oxidation and reduction concepts  8.2. Oxidation number and its applications  8.3. Redox reactions in terms of electron transfer  8.4. Balancing redox reactions (oxidation number and ion-electron methods)  8.5. Types of redox reactions  8.6. Electrochemical Cells and Redox Reactions
  9. Hydrogen  9.1. Position of Hydrogen in the Periodic Table  9.2. Isotopes of hydrogen  9.3. Preparation of Hydrogen  9.4. Properties of Hydrogen  9.5. Hydrides and their classification  9.6. Water and heavy water  9.7. Hydrogen peroxide and its properties  9.8. Uses of Hydrogen and Its Compounds
  10. S-block elements (alkali and alkaline earth metals)  10.1. Group 1 Elements - Properties and Trends  10.2. Group 2 Elements - Properties and Trends  10.3. Unusual properties of lithium and beryllium  10.4. Important compounds of sodium and their uses  10.5. Important Compounds of Magnesium and Calcium
  11. Some p-block elements  11.1. General Introduction to p-Block Elements  11.2. Group 13 Elements  11.2.1. Boron and its compounds  11.3. Group 14 Elements  11.3.1. Carbon and its allotropes  11.3.2. Important Compounds of Carbon and Silicon
  12. Organic Chemistry - Some Basic Principles and Techniques  12.1. Classification and Nomenclature of Organic Compounds  12.2. Structural representation of organic compounds  12.3. Classification of organic reactions  12.4. Electronic Effects in Organic Chemistry  12.4.1. Inductive effect  12.4.2. Resonance effect  12.4.3. Hyperconjugation  12.5. Reaction mechanism and intermediate species  12.6. Purification and qualitative analysis of organic compounds
  13. Hydrocarbons  13.1. Hydrocarbons  13.1.1. Preparation and Properties of Alkenes  13.2. alkene  13.2.1. Preparation and Properties of Alkenes  13.2.2. Electrophilic addition reactions  13.3. Alkynes  13.3.1. Preparation and Properties of Alkynes  13.4. Aromatic hydrocarbons  13.4.1. Structure and properties of benzene  13.4.2. Electrophilic substitution reactions of benzene
  14. Environmental Chemistry  14.1. Environmental Pollution  14.2. Atmospheric pollution and the greenhouse effect  14.3. Water pollution and treatment methods  14.4. Soil pollution and its effects  14.5. Industrial waste and its treatment  14.6. Strategies for pollution control

Grade 11 ↓


Hydrogen


Hydrogen is the first element of the periodic table, with the symbol H and atomic number 1. It is the simplest and most abundant element in the universe, making up about 75% of the mass of the universe's basic elements. Despite its prevalence in the universe, on Earth, it is usually found in combination with other elements, such as oxygen (H2O) in water.

Discovery and history

Hydrogen was first identified as a separate element by English scientist Henry Cavendish in 1766. It was named by Antoine Lavoisier in 1783. The name hydrogen is derived from the Greek words "hydro" meaning water and "genes" meaning creator. This is because when hydrogen burns, it creates water.

Physical properties

Hydrogen is a colorless, odorless and tasteless gas at room temperature. It is the lightest and smallest of all elements. Some important physical properties of hydrogen are as follows:

  • State at room temperature: Gas
  • Density: Hydrogen gas has the lowest density among all gases.
  • Boiling point and melting point: The boiling point of hydrogen is -252.87°C and melting point is -259.16°C.

Chemical properties

Hydrogen is chemically reactive under many conditions and forms compounds with most elements. Here are some important chemical properties:

  • Combustion: Hydrogen burns in oxygen to form water.
    2H2 + O2 → 2H2O
  • Reactivity with other elements: Hydrogen reacts with halogens such as chlorine and fluorine to form hydrogen halides.
  • Isotopes: Hydrogen has three natural isotopes: protium (1H), deuterium (2H), and tritium (3H).

The presence of hydrogen

Hydrogen is widely distributed in water and organic compounds. It is less common as a free element in the Earth's crust, but is prevalent in the atmosphere and outer space.

  • In water: Water is a major source of hydrogen.
  • In the atmosphere: Only trace amounts of hydrogen are found.

Uses of hydrogen

Hydrogen has many uses in a variety of industries:

  • Fuel: Used as a clean fuel alternative, hydrogen could power cars, trucks and even spacecraft.
  • Ammonia production: An essential ingredient in fertilizers, hydrogen reacts with nitrogen to produce ammonia.
    N2 + 3H2 → 2NH3
  • Hydrogenation of fats and oils: Hydrogen used in the food industry is added to oils to make margarine and butter.

Visual representation of the hydrogen atom

Electron Hydrogen atom model

Hydrogen isotopes

As mentioned earlier, hydrogen has three main isotopes:

  1. Protium (1H): The most common isotope, with one proton and no neutrons.
  2. Deuterium (2H or D): Contains one proton and one neutron.
  3. Tritium (3H or T): Has one proton and two neutrons, and is radioactive.

These isotopes behave differently in chemical reactions than non-radioactive hydrogen, especially tritium, which is dangerous because of its radioactivity.

Hydrogen bonds

Hydrogen bonds are a special type of attractive interaction that exists between an electronegative atom and a hydrogen atom bonded to another electronegative atom. These are particularly important in water molecules, significantly affecting the properties of water. For example:

H2O ---- H2O

The properties of water, such as its high boiling point, high surface tension, and solvation ability, are due to hydrogen bonding.

Hydrogen economy

The hydrogen economy has been proposed as a future economy in which hydrogen is used as a major energy carrier. This is due to its potential as a clean, abundant and efficient energy source. The idea is to produce and distribute hydrogen primarily from sustainable sources.

Challenges and future prospects

Despite its potential, there are some challenges in using hydrogen as a major energy source:

  • Storage and transportation: Hydrogen has a low energy density, posing challenges in storage and transportation.
  • Production: Currently, producing hydrogen on a large scale is expensive.

However, advances in technology and infrastructure could make hydrogen the basis for the transition to sustainable energy practices.

Conclusion

Hydrogen is a fascinating element that plays a vital role in both chemistry and the potential future of global energy systems. Its unique properties and potential applications make it an area of ongoing research and interest.


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