physci

• Contributors on the periodic table:

  • Doberiener (Law of Triads)
  • Newland (Law of Octaves)
  • Meyer (6 families)
  • Mendeleev (Atomic mass Periodic Law)
  • Moseley (Atomic number Modern PL)
• Electronegativity is a measure of how much an atom attracts electron pairs in a chemical bond
• Pauling Scale is used to measure electronegativity, where the higher the electronegativity, the greater the attraction
• Electron Affinity is a measure of an atom's energy changes when an electron is added to a gaseous atom
• Ionization Energy is the minimum energy required to remove an electron from a neutral atom when the molecule is in the gaseous state
• Elements constitute the simplest chemical substances in which all the atoms are exactly the same, like H, N, F, O, I, Cl, Bi
• Compounds are chemical substances made up of two or more elements that are chemically bound together in a fixed ratio, like H2, N2, F2, O2, I2, Cl2, Bi2
• Contributors on Chemical Bonding:

  • Boyle (Elements)
  • Priestly (Combustion)
  • Proust (Law of Definite Proportion)
  • Dalton (Law of Multiple Proportion)
  • Lavosier (Law of conservation of mass)
• Chemical Bonds refer to the formation of a chemical bond between two or more atoms, molecules, or ions to give rise to a chemical compound
• Types of Chemical Bonds:

  1. Ionic bond: metal atom loses electron(s) to nonmetal atom

  2. Covalent bonds: two nonmetal atoms share electrons

  3. Hydrogen bonds: hydrogen attracts an electronegative atom electrostatically

  4. Metallic Bonds: positive metal ions attract conducting electrons
• Polyatomic Ion is made up of two or more atoms, classified as cations and anions depending on the charge
• Covalent bonds result from the sharing of one or more valence electrons from one atom to another, existing between two nonmetals
• Electronegativity is the tendency of an atom in a molecule to attract the shared pair of electrons towards itself, measured by Linus Pauling
• Localized Electron Bonding Model includes the description of valence electron arrangement (Lewis structure), prediction of geometry (VSEPR model), and description of atomic orbital types used to share electrons or hold lone pairs
• Exception to Octet Rule:

  • Incomplete octet: B/Be tends to form compounds with fewer than eight electrons around it
  • Expanded Octet: Exceeds the octet rule, typically for third-row (or higher) elements
• VSEPR (Valence Shell Electron Pair Repulsion) theory explains how atoms arrange themselves to minimize electron pair repulsion, affecting the molecule's geometry
• Stoichiometry involves calculating products and reactants in a chemical reaction, using relationships between them to determine quantitative data
• Molar Mass is the mass of a compound divided by the amount of the substance present, measured in g/mol or kg/mol
• Mole is the amount of substance containing the same number of entities as the number of atoms in a sample of pure 12C weighing exactly 12 g
• Mole Ratio is the ratio between any two substances in a chemical reaction, known as the molar ratio or mole-to-mole ratio
• Chemical Reaction is a process where reactants are converted to products, with indicators like color change, effervescence, precipitation, and energy change
• Collision theory states that for a reaction to occur, reactant molecules must collide with proper orientation and enough energy, with factors like collision, energy, and orientation affecting the rate of reaction
• Factors affecting the rate of reaction:

  • Surface Area
  • Concentration Of Reactant
  • Temperature
  • Presence of a catalyst
  • Pressure
• Biomolecules are compounds found in living organisms, including carbohydrates, lipids, nucleic acids, and proteins
• Carbon is the central element in biomolecules, forming stable covalent bonds in chains or rings with 4 valence electrons
• Monomers are made into polymers via dehydration reactions, while polymers are broken down into monomers via hydrolysis reactions
• Carbohydrates are made of carbon, hydrogen, and oxygen, with monosaccharides, disaccharides, and polysaccharides as their components
• Lipids are hydrophobic, nonpolar compounds like fats, oils, waxes, phospholipids, and steroids, with saturated and unsaturated fats as their types
• Functions of Lipids include being an energy source, protecting organs, insulating the body, generating heat, and giving cell membranes structure
• Proteins have various functions like enzyme catalysts, defense, transport and support, motion, regulation, and storage
• Nucleic Acids are responsible for the transmission of hereditary characters, protein synthesis, and DNA fingerprinting in forensic studies
• Periodic Table is the arrangement of all the elements known to man in accordance with their increasing atomic number and recurring chemical properties.
• Electronegativity Difference is the bonding type is inextricably linked to the absolute difference of electronegativity values
• In Greek, stoikhein means element and metron means measure, so stoichiometry literally translated means the measure of elements.
• Indicators of a Chemical Reaction

  • Color Change
  • Effervescence
  • Precipitation
  • Energy (temperature change)
• Surface area is the measure

  of how much exposed area a solid object has, expressed in square units
• Concentration Of Reactant is the amount of substance

  present
• Temperature is the measurement of the average kinetic energy of the substance
• Presence of a catalyst is a catalyst speeds up a

  chemical reaction, without being consumed by the

  reaction. It increases the reaction rate

  by lowering the activation

  energy.
• Pressure is defined to be the amount of force exerted per area.