Grade 10 Science Notes: Chemistry, Biology, Ecology, and Optics

Posted on Jun 26, 2024 in Chemistry

Grade 10 Chemistry

1. Atomic Structure

Atoms and Elements

  • Atoms: Smallest unit of matter, consists of protons, neutrons, and electrons.
  • Protons: Positively charged, found in the nucleus.
  • Neutrons: Neutral, found in the nucleus.
  • Electrons: Negatively charged, orbit the nucleus.
  • Atomic Number (Z): Number of protons in an atom.
  • Mass Number (A): Total number of protons and neutrons.
  • Isotopes: Atoms of the same element with different numbers of neutrons.

Electron Configuration

  • Electron Shells: Energy levels where electrons are found.
  • Configuration: Distribution of electrons across different shells (e.g., 2-8-1 for sodium).
  • Valence Electrons: Electrons in the outermost shell, determine chemical reactivity and bonding.

2. Periodic Table

Structure

  • Groups: Vertical columns (1-18), elements in a group have similar properties.
  • Periods: Horizontal rows, properties change progressively across a period.

Categories

  • Metals: Good conductors of heat and electricity, malleable, ductile.
  • Non-metals: Poor conductors, brittle when solid.
  • Metalloids: Properties of both metals and non-metals.

Important Groups

  • Group 1: Alkali metals (e.g., Lithium, Sodium), 1 valence electron.
  • Group 2: Alkaline earth metals (e.g., Magnesium, Calcium), 2 valence electrons.
  • Group 13: Boron group (e.g., Boron, Aluminum), 3 valence electrons.
  • Group 14: Carbon group (e.g., Carbon, Silicon), 4 valence electrons.
  • Group 15: Nitrogen group (e.g., Nitrogen, Phosphorus), 5 valence electrons.
  • Group 16: Oxygen group (e.g., Oxygen, Sulfur), 6 valence electrons.
  • Group 17: Halogens (e.g., Fluorine, Chlorine), 7 valence electrons.
  • Group 18: Noble gases (e.g., Helium, Neon), 8 valence electrons (except Helium, which has 2).

3. Chemical Bonding

Ionic Bonds

  • Formation: Transfer of electrons from a metal to a non-metal.
  • Ions: Charged atoms (cations are positive, anions are negative).
  • Properties: High melting and boiling points, conduct electricity when molten or dissolved.

Covalent Bonds

  • Formation: Sharing of electron pairs between non-metals.
  • Molecules: Groups of atoms bonded covalently (e.g., H₂O, CO₂).
  • Properties: Low melting and boiling points, poor electrical conductivity.

Metallic Bonds

  • Formation: Sea of shared free electrons among metal atoms.
  • Properties: Good electrical and thermal conductivity, malleable, ductile.

4. Chemical Reactions

Types of Reactions

  • Synthesis: A + B → AB
  • Decomposition: AB → A + B
  • Single Displacement: A + BC → AC + B
  • Double Displacement: AB + CD → AD + CB
  • Combustion: Hydrocarbon + O₂ → CO₂ + H₂O

Balancing Equations

  • Law of Conservation of Mass: Mass is neither created nor destroyed in a chemical reaction.
  • Steps:
    1. Write the unbalanced equation.
    2. Count atoms of each element.
    3. Use coefficients to balance atoms.
    4. Check the balance.

Acids and Bases

  • Acids: Produce H⁺ ions in solution (e.g., HCl).
  • Bases: Produce OH⁻ ions in solution (e.g., NaOH).
  • pH Scale: Measures acidity/alkalinity (0-14 scale; <7 acidic, >7 basic, 7 neutral).

Neutralization

  • Reaction: Acid + Base → Salt + Water
  • Example: HCl + NaOH → NaCl + H₂O

5. Naming Compounds

Ionic Compounds

  • Binary Ionic Compounds: Consist of two elements.
  • Naming Rule: Metal name + non-metal name with “-ide” suffix.
  • Example: NaCl = Sodium Chloride
  • Transition Metals: Include the charge in Roman numerals.
  • Example: FeCl₂ = Iron(II) Chloride

Covalent (Molecular) Compounds

  • Binary Covalent Compounds: Consist of two non-metals.
  • Naming Rule: Use prefixes to indicate the number of each element.
  • Prefixes: 1 = mono-, 2 = di-, 3 = tri-, 4 = tetra-, 5 = penta-, 6 = hexa-, 7 = hepta-, 8 = octa-, 9 = nona-, 10 = deca-.
  • Example: CO₂ = Carbon Dioxide, P₂O₅ = Diphosphorus Pentoxide

Acids

  • Binary Acids: Contain hydrogen and one other non-metal.
  • Naming Rule: “Hydro-” prefix + non-metal root + “-ic” suffix + “acid.”
  • Example: HCl = Hydrochloric Acid
  • Oxyacids: Contain hydrogen, oxygen, and another element.
  • Naming Rule: Root of the polyatomic ion + “-ic” (if ion ends in “-ate”) or “-ous” (if ion ends in “-ite”) + “acid.”
  • Example: H₂SO₄ (sulfate) = Sulfuric Acid, H₂SO₃ (sulfite) = Sulfurous Acid

Polyatomic Ions

  • Common Polyatomic Ions:
    Ammonium: NH₄⁺
    Hydroxide: OH⁻
    Nitrate: NO₃⁻
    Sulfate: SO₄²⁻
    Carbonate: CO₃²⁻
    Phosphate: PO₄³⁻
  • Naming Rule: Name of the metal + name of the polyatomic ion.
  • Example: NaNO₃ = Sodium Nitrate, CaCO₃ = Calcium Carbonate.

Steps to Balance a Chemical Equation

  1. Write the Unbalanced Equation
    Start with the reactants on the left side and the products on the right side.
    Example: C₃H₈ + O₂ → CO₂ + H₂O
  2. Count the Number of Atoms of Each Element
    List the number of atoms of each element present in the reactants and products.
    Example:
    Reactants: C₃H₈ (3 C, 8 H) and O₂ (2 O).
    Products: CO₂ (1 C, 2 O) and H₂O (2 H, 1 O).
  3. Balance One Element at a Time
    Start with an element that appears in only one reactant and one product. Adjust coefficients (numbers in front of compounds) to balance each element.
    Example:
    Balance Carbon (C): C₃H₈ + O₂ → 3CO₂ + H₂O (Now 3 C atoms on both sides)
    Balance Hydrogen (H): C₃H₈ + O₂ → 3CO₂ + 4H₂O (Now 8 H atoms on both sides)
    Balance Oxygen (O): C₃H₈ + 5O₂ → 3CO₂ + 4H₂O (Now 10 O atoms on both sides: 5 O₂ → 10 O, 3 CO₂ → 6 O, 4 H₂O → 4 O)

Grade 10 Ecology

1. Ecosystems

  • Components: Biotic (living) and Abiotic (non-living)
  • Types: Terrestrial (forests, deserts) and Aquatic (freshwater, marine)
  • Energy Flow: Sun → Producers (plants) → Consumers (herbivores, carnivores) → Decomposers (fungi, bacteria)

2. Food Chains and Webs

  • Food Chain: Linear sequence of organisms where nutrients and energy pass.
  • Food Web: Complex network of interconnected food chains.

3. Trophic Levels

  • Primary Producers: Plants, algae
  • Primary Consumers: Herbivores
  • Secondary Consumers: Carnivores that eat herbivores
  • Tertiary Consumers: Carnivores that eat other carnivores

4. Biogeochemical Cycles

  • Water Cycle: Evaporation, condensation, precipitation
  • Carbon Cycle: Photosynthesis, respiration, decomposition, fossil fuels
  • Nitrogen Cycle: Nitrogen fixation, nitrification, assimilation, ammonification, denitrification

5. Population Dynamics

  • Carrying Capacity: Maximum population size an environment can sustain
  • Limiting Factors: Resources, predation, disease, climate
  • Growth Models: Exponential and logistic growth

6. Biodiversity

  • Importance: Ecosystem stability, genetic variation, resource availability
  • Threats: Habitat destruction, pollution, overexploitation, invasive species, climate change

Grade 10 Biology

1. Cell Biology

  • Cell Theory: All living things are made of cells, the cell is the basic unit of life, all cells come from pre-existing cells
  • Cell Structures:
    • Prokaryotic Cells: No nucleus, simple structure (bacteria)
    • Eukaryotic Cells: Nucleus, complex organelles (animals, plants)
  • Organelles: Nucleus, mitochondria, ribosomes, endoplasmic reticulum, Golgi apparatus, lysosomes, chloroplasts (in plants), cell membrane, cell wall (in plants)

2. Genetics

  • DNA Structure: Double helix, nucleotides (adenine, thymine, cytosine, guanine)
  • Replication: DNA copying process
  • Transcription and Translation: From DNA to mRNA to protein
  • Mendelian Genetics: Dominant and recessive traits, Punnett squares, genotype, phenotype
  • Genetic Variation: Mutation, recombination, sexual reproduction

3. Evolution

  • Natural Selection: Survival of the fittest, adaptation, speciation
  • Evidence of Evolution: Fossils, comparative anatomy, molecular biology, biogeography
  • Mechanisms: Mutation, gene flow, genetic drift, selection

4. Human Biology

  • Body Systems:
    • Circulatory: Heart, blood, blood vessels
    • Respiratory: Lungs, trachea, bronchi
    • Digestive: Stomach, intestines, liver, pancreas
    • Nervous: Brain, spinal cord, nerves
    • Skeletal: Bones, joints
    • Muscular: Muscles, tendons
    • Reproductive: Male and female reproductive organs

Grade 10 Optics

1. Properties of Light

  • Nature: Electromagnetic wave, particle (photon)
  • Speed: 3 x 10⁸ m/s in vacuum
  • Behavior: Reflection, refraction, diffraction, interference

2. Reflection

  • Laws of Reflection: Angle of incidence equals angle of reflection
  • Types of Mirrors:
    • Plane Mirror: Upright, virtual image
    • Concave Mirror: Converging, real or virtual image
    • Convex Mirror: Diverging, virtual image

3. Refraction

  • Snell’s Law: n₁ sin θ₁ = n₂ sin θ₂
  • Index of Refraction: n = c/v (c: speed of light in vacuum, v: speed of light in medium)
  • Lenses:
    • Convex (Converging) Lens: Focuses light, real or virtual image
    • Concave (Diverging) Lens: Spreads light, virtual image

4. Optical Instruments

  • Microscope: Uses lenses to magnify small objects
  • Telescope: Uses lenses or mirrors to observe distant objects
  • Camera: Uses lens to focus light on a photosensitive surface

5. Human Eye

  • Structure: Cornea, lens, retina, optic nerve
  • Function: Light enters through cornea and lens, focused on retina, converted to neural signals, transmitted to brain

6. Wave-Particle Duality

  • Concept: Light exhibits both wave-like and particle-like properties
  • Experiments: Double-slit experiment (wave), photoelectric effect (particle)

7. Color

  • Visible Spectrum: Red, orange, yellow, green, blue, indigo, violet (ROYGBIV)
  • Color Addition: Primary colors (red, green, blue) combine to form white light
  • Color Subtraction: Primary pigments (cyan, magenta, yellow) combine to absorb light and produce color