Magnetizationmagnetism And Matter Topic
Toppers’ Detailed Notes
Topic: The Structure of an Atom
Reference: NCERT Class 11 Chemistry, Chapter 2
Notes:
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John Dalton’s atomic theory:
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Matter consists of tiny, indivisible particles called atoms.
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All atoms of a given element are identical in mass and other properties.
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Atoms of different elements have different masses and properties.
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Atoms can combine with each other to form compounds.
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Subatomic particles:
- Protons: positively charged particles found in the nucleus. Their number is represented by (p)
- Neutrons: neutral particles found in the nucleus. Their number is represented by (n).
- Electrons: negatively charged particles that orbit the nucleus. Their number is represented by (e).
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Atomic number (Z):
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The number of protons in an atom is called the atomic number.
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It is unique for each element and determines its position in the periodic table.
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Mass number (A):
- The total number of protons and neutrons in an atom’s nucleus is called its mass number.
- It is approximately equal to the atomic mass.
Examples and Explanations:
- ({17}Cl^{35}) and ({17}Cl^{37}) represent isotopes of chlorine.
- Both have 17 protons but different numbers of neutrons.
- Since they have the same atomic number (Z=17), they are both chlorine atoms.
Topic: Chemical Bonding
Reference: NCERT Class 11 Chemistry, Chapter 4
Notes:
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Chemical bonding: the force that holds atoms together to form compounds.
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Types of chemical bonds:
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Ionic bonding: formed by the transfer of electrons from one atom to another, resulting in oppositely charged ions.
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Covalent bonding: formed by the sharing of electrons between atoms.
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Metallic bonding: formed by the attraction between positively charged metal ions and the surrounding sea of mobile electrons.
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Lewis dot structures:
- Represent the valence electrons of atoms using dots around their symbols.
- Useful for predicting the type of bonding that will occur between atoms.
Examples and Explanations:
- In sodium chloride (NaCl), sodium loses an electron to chlorine, resulting in Na+ and Cl- ions held together by ionic bonding.
- In methane (CH4), each carbon atom shares four electrons with four hydrogen atoms, forming four covalent bonds.
Topic: Thermodynamics
Reference: NCERT Class 12 Chemistry, Chapter 5
Notes:
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Thermodynamics:
- The study of heat and its relation to other forms of energy.
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Deals with the energy changes that occur during chemical reactions, phase transitions, and other physical processes.
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Three laws of thermodynamics:
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First law: Energy can neither be created nor destroyed, only transferred or transformed.
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Second law: In any spontaneous process, the entropy (measure of disorder) always increases.
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Third law: As the temperature approaches absolute zero, the entropy of a perfect crystal approaches zero.
Examples and Explanations:
- When a fuel burns, its chemical energy is converted into heat energy and light energy.
- In a refrigerator, heat is transferred from the inside to the outside, cooling the interior.
Topic: Carbon Compounds
Reference: NCERT Class 11 Chemistry, Chapter 13
Notes:
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Carbon compounds:
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Molecules that contain carbon atoms, forming the basis of organic chemistry.
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Diverse and essential for life, including carbohydrates, proteins, lipids, and nucleic acids.
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Functional groups:
- Specific arrangements of atoms within carbon compounds that give them characteristic properties.
- Examples include:
- Hydroxyl (-OH)
- Carbonyl (C=O)
- Amino (-NH2)
- Carboxylic acid (-COOH)
Examples and Explanations:
- Ethanol contains a hydroxyl group, giving it the ability to dissolve in water and react with other compounds.
- Proteins contain amino acids, which are linked together by peptide bonds to form long chains.