The concept of "Building Blocks" in science refers to the fundamental components that make up matter and the universe. This encompasses understanding atoms, elements, compounds, and the periodic table, as well as chemical bonding and the behavior of materials. This section forms a foundational understanding necessary for exploring more complex scientific principles and phenomena.

Atoms and Elements

• Atoms

  • The smallest unit of an element that retains the properties of that element.

  • Consists of a nucleus containing protons and neutrons, surrounded by electrons in shells.

  • Protons - Positively charged particles found in the nucleus. The number of protons (atomic number) defines the element.

  • Neutrons - Neutral particles found in the nucleus. Together with protons, they make up the atomic mass.

  • Electrons - Negatively charged particles orbiting the nucleus in electron shells. The arrangement of electrons determines the chemical properties and reactivity of the element.

  • Isotopes - Atoms of the same element that have different numbers of neutrons. For example, Carbon-12 and Carbon-14.

• Elements

  • Pure substances consist of only one type of atom.

  • Represented by chemical symbols (e.g., H for hydrogen, O for oxygen).

  • Organized in the periodic table based on atomic number.

  • Example: 

    • Carbon (C)

      Oxygen (O)

    • Hydrogen (H).

The Periodic Table

• Structure

  • Rows called periods and columns called groups.

  • Elements in the same group have similar chemical properties because they have the same number of electrons in their outer shell.

  • Example:

    • Group 1 elements like lithium (Li), sodium (Na), and potassium (K) have one electron in their outer shell and are very reactive.

• Groups

  • Group 1 (Alkali Metals): Highly reactive, especially with water (e.g., sodium, potassium).

  • Group 2 (Alkaline Earth Metals): Reactive metals (e.g., magnesium, calcium).

  • Group 7 (Halogens): Very reactive non-metals (e.g., chlorine, fluorine).

  • Group 0 (Noble Gases): Unreactive gasses (e.g., helium, neon) with a full outer electron shell.

• Periods

  • Indicate the number of electron shells around the nucleus.

  • As you move across a period, the number of protons and electrons increases.

Compounds and Mixtures

• Compounds

  • Substances formed when two or more elements chemically bond together.

  • Represented by chemical formulas (e.g., H₂O for water, CO₂ for carbon dioxide).

  • Properties of compounds are different from their constituent elements.

  • Types of bonding: Ionic, covalent, and metallic.

  • Examples: 

    • Sodium chloride (NaCl)

    • Water (H₂O)

    • Carbon dioxide (CO₂).

• Mixtures

  • Combinations of two or more substances that are not chemically bonded.

  • Can be separated by physical methods (filtration, distillation).

  • Examples: 

    • Air (mixture of gasses)

    • Salt water (mixture of salt and water).

Chemical Bonding

• Ionic Bonding

  • Occurs between metals and nonmetals.

  • Involves the transfer of electrons from one atom to another, resulting in the formation of ions.

  • Example:

    • Sodium chloride (NaCl), where sodium loses an electron to become Na⁺ and chlorine gains an electron to become Cl⁻.

• Covalent Bonding

  • Occurs between nonmetals.

  • Involves the sharing of electrons between atoms.

  • Example:

    • Water (H₂O), where each hydrogen atom shares electrons with the oxygen atom.

• Metallic Bonding

  • Occurs between metal atoms.

  • Involves a sea of delocalized electrons surrounding positive metal ions.

  • Provides metals with properties like conductivity and malleability.

  • Example:

    • Copper (Cu)

    • Aluminum (Al).

Chemical Reactions

• Reactions

  • Processes in which substances (reactants) transform into new substances (products).

  • Indicators include color change, temperature change, gas production, and precipitate formation.

• Types of Reactions

  • Combustion - Burning in oxygen to produce heat and light (e.g., burning methane CH₄ + 2O₂ → CO₂ + 2H₂O).

  • Neutralization - Acid reacts with a base to form salt and water (e.g., HCl + NaOH → NaCl + H₂O).

  • Displacement - A more reactive element displaces a less reactive element from a compound (e.g., Zn + CuSO₄ → ZnSO₄ + Cu).

Conservation of Mass

• Law of Conservation of Mass

  • Mass is neither created nor destroyed in a chemical reaction.

  • The mass of the reactants equals the mass of the products.

  • Example:

    • In the reaction of hydrogen and oxygen to form water, the total mass of hydrogen and oxygen equals the mass of the produced water.

States of Matter

• Solids

  • Particles are closely packed in a fixed arrangement.

  • Definite shape and volume.

  • Particles vibrate in place but do not move freely.

• Liquids

  • Particles are close together but can move past each other.

  • Definite volume but takes the shape of its container.

  • Particles have more energy than in solids, allowing them to flow.

• Gasses

  • Particles are far apart and move freely.

  • No definite shape or volume; they expand to fill their container.

  • Particles have the most energy and move rapidly in all directions.

Changing States

• Melting - Solid to liquid 

  • (ice melting to water)

• Freezing - Liquid to solid 

  • (water freezing to ice)

• Evaporation - Liquid to gas 

  • (water evaporating to vapor)

• Condensation - Gas to liquid 

  • (water vapor condensing to liquid)

• Sublimation - Solid to gas without becoming liquid 

  • (dry ice to carbon dioxide gas)

The Mole and Chemical Calculations

• The Mole

  • A unit of measurement for amount of substance.

  • One mole contains 6.022 × 10²³ particles (Avogadro's number).

• Molar Mass

  • The mass of one mole of a substance.

  • Calculated by summing the atomic masses of all atoms in a molecule (e.g., the molar mass of H₂O is 18 g/mol).

• Calculations:

  • To find the number of moles: 

Moles = Mass / Molar Mass 

• To find the mass: 

Mass = Moles × Molar Mass 

• Example:

  • To find the mass of 2 moles of water, calculate 2 × 18 = 36 grams.

Chemical Equations and Stoichiometry

• Balancing Chemical Equations

  • Ensures the law of conservation of mass is followed.

  • Reactants and products must have the same number of each type of atom.

  • Example:

    • Balancing the equation for the combustion of methane: CH₄ + 2O₂ → CO₂ + 2H₂O 

• Stoichiometry

  • The calculation of reactants and products in chemical reactions.

  • Uses balanced equations to determine the proportions of substances.

  • Example:

    • Using the balanced equation to determine how much oxygen is needed to react with 5 grams of methane.

Atomic Structure and Electron Configuration

• Atomic Structure

  • Atoms consist of a nucleus (protons and neutrons) and electrons in orbitals.

  • The arrangement of electrons determines the chemical properties of an element.

• Electron Configuration

  • The distribution of electrons in an atom's electron shells.

  • Example:

    • The electron configuration of carbon is 1s²2s²2p².

Chemical Properties and Periodic Trends

• Chemical Properties

  • Determined by the number of electrons in the outer shell.

  • Elements in the same group have similar chemical properties.

• Periodic Trends

  • Patterns in the periodic table that show changes in properties across periods and groups.

  • Examples:

    • Atomic Radius: Decreases across a period, increases down a group.

    • Ionization Energy: Increases across a period, decreases down a group.

    • Electronegativity: Increases across a period, decreases down a group.

The Reactivity Series and Metal Extraction

• Reactivity Series

  • A list of metals arranged in order of decreasing reactivity.

  • More reactive metals displace less reactive metals from their compounds.

  • Example:

    • Potassium is more reactive than zinc, which is more reactive than copper.

• Metal Extraction

  • The process of obtaining metals from their ores.

  • Methods include reduction with carbon (for less reactive metals) and electrolysis (for more reactive metals).

  • Example:

    • Extracting iron from hematite using a blast furnace.

Polymers and Macromolecules

• Polymers

  • Large molecules made up of repeating units (monomers).

  • Example:

    • Polyethylene, made from ethylene monomers.

• Natural and Synthetic Polymers

  • Natural polymers include proteins, DNA, and cellulose.

  • Synthetic polymers include plastics like polystyrene and nylon.

• Macromolecules

  • Very large molecules, often composed of thousands of atoms.

  • Important in biology and materials science.

Biological Macromolecules

• Proteins

  • Structure: Composed of long chains of amino acids linked by peptide bonds.

  • Functions: Enzymatic activity (e.g., amylase), structural support (e.g., collagen), transport (e.g., hemoglobin), and signaling (e.g., insulin).

  • Example:

    • Hemoglobin, which carries oxygen in the blood.

• Nucleic Acids

  • Structure: Long chains of nucleotides, which include a sugar, phosphate group, and nitrogenous base.

  • Functions: Storage and transmission of genetic information.

  • Types:

    • DNA (Deoxyribonucleic Acid): Stores genetic information.

    • RNA (Ribonucleic Acid): Transfers genetic code needed for protein synthesis.

• Example:

  • DNA, which carries genetic instructions for the development and functioning of living organisms.

• Carbohydrates

  • Structure: Composed of carbon, hydrogen, and oxygen atoms, typically in a ratio of 1:2:1 (CnH2nOn).

  • Functions: Provide energy, store energy, and serve as structural components.

  • Types:

    • Monosaccharides: Simple sugars (e.g., glucose, fructose).

    • Disaccharides: Two monosaccharides linked together (e.g., sucrose, lactose).

    • Polysaccharides: Long chains of monosaccharides.

      • Starch: Energy storage in plants.

      • Glycogen: Energy storage in animals.

      • Cellulose: Structural component in plant cell walls.

      • Chitin: Structural component in the exoskeleton of arthropods and cell walls of fungi.

• Example:

  • Glucose, a primary source of energy for cells.

• Lipids

  • Structure: Composed mainly of carbon and hydrogen atoms and are hydrophobic.

  • Functions: Energy storage, cell membrane structure, and signaling.

  • Types:

    • Fats and Oils: Energy storage.

    • Phospholipids: Major component of cell membranes.

    • Steroids: Hormones and signaling molecules.

  • Example:

    • Phospholipids, which form the bilayer of cell membranes.

Synthetic Macromolecules

• Plastics

  • Structure: Long chains of synthetic polymers.

  • Uses: Packaging, construction materials, household items, and medical devices.

  • Types:

    • Polyethylene (PE): Used in plastic bags and bottles.

    • Polyvinyl Chloride (PVC): Used in pipes and flooring.

  • Example:

    • Polyethylene, which is commonly used in plastic bottles.

• Nylon

  • Structure: Synthetic polymer composed of repeating units linked by amide bonds.

  • Uses: Textiles, fishing lines, and parachutes.

  • Example:

    • Nylon-6,6, used in fabrics and carpets.

• Polyesters

  • Structure: Polymers formed from ester monomers.

  • Uses: Fabrics, packaging, and plastic bottles.

  • Example:

    • Polyethylene terephthalate (PET), used in clothing and beverage containers.

• Polystyrene

  • Structure: Synthetic polymer made from styrene monomers.

  • Uses: Packaging materials, insulation, and disposable cutlery.

  • Example: 

    • Expanded polystyrene (EPS), used in foam packaging and insulation.

Natural Macromolecules

• Natural Rubber

  • Structure: Polyisoprene, a polymer of isoprene units.

  • Uses: Tires, footwear, and elastic materials.

  • Example:

    • Natural rubber from the latex of the rubber tree.

• Chitin

  • Structure: Long chains of N-acetylglucosamine, a derivative of glucose.

  • Uses: Structural component in the exoskeletons of arthropods and cell walls of fungi.

  • Example:

    • Chitin in the exoskeleton of crabs and insects.

• Lignin

  • Structure: Complex polymer of aromatic alcohols.

  • Uses: Provides rigidity to plant cell walls.

  • Example:

    • Lignin in wood, contributing to its strength and resistance to decay.

Nanotechnology

• Nanoparticles

  • Particles between 1 and 100 nanometers in size.

  • Exhibit unique properties different from bulk material.

  • Used in medicine, electronics, and materials science.

• Applications

  • Medicine: Targeted drug delivery, cancer treatment.

  • Electronics: Improving the performance of semiconductors and batteries.

  • Materials: Enhancing strength, flexibility, and durability of materials.

Examples and Applications

• Chemical Reactions in Daily Life

  • Combustion: Fuel burning in cars.

  • Neutralization: Using antacids to relieve indigestion.

  • Displacement: Iron nail placed in copper sulfate solution, iron displaces copper.

• Importance of Chemical Bonding:

  • Ionic Compounds: Used in salts and minerals.

  • Covalent Compounds: Found in water, proteins, and DNA.

  • Metallic Bonds: Provide metals with properties essential for construction and electronics.