Unit 2 Slides AY242

Unit 2: Introductory Chemistry Honors Biology

Page 2: Chemistry Overview

• Definition of Chemistry

  • Deals with chemical and physical interactions of matter.

  • Composed of about 100 different atoms.

Page 3: Atoms

• Atoms

  • Basic unit of an element for chemical combinations.

  • Most atoms originated from the universe's birth.

Page 4-7: Atomic Structure

• Composition of Atoms

  • Nucleus at the center with surrounding electrons.

  • Nucleus contains protons (positive) and neutrons (neutral).

  • Electrons (negative) reside outside the nucleus.

• Electron Movement

  • Electrons are much smaller than protons/neutrons and are in constant motion.

  • Chemical properties depend on the number and arrangement of electrons.

Page 8-9: Subatomic Particles

• Particle Characteristics

  • Electrons: mass of 9.10 x 10^-28 grams, charge of -1.602 x 10^-19 coulombs.

  • Protons determine chemical identity; electrons determine behavior.

  • Neutrons provide mass and stability.

Page 10-11: Chemical Symbols & Atomic Number

• Atomic Number (Z)

  • Number of protons in an atom.

• Mass Number (A)

  • Total of protons and neutrons.

• Neutral Atoms

  • Equal number of protons and electrons.

Page 12: Isotopes

• Definition

  • Same atomic number, different mass numbers (different neutrons).

• Examples

  • Hydrogen isotopes: Protium, Deuterium, Tritium.

  • Iron isotopes: Iron-56, Iron-55.

Page 13: Core vs. Valence Electrons

• Classification

  • Core electrons: inner electrons.

  • Valence electrons: outermost electrons, involved in bonding.

Page 14-18: Compounds

• Definition of Compounds

  • Formed when two or more elements combine in definite proportions.

• Types of Compounds

  • Molecular Compounds: Atoms share electrons (e.g., ammonia).

  • Ionic Compounds: Formed from ions in a 3D network (e.g., sodium chloride).

Page 19-22: Molecular Interactions

• van der Waals Forces

  • Weak interactions due to electron movement.

• Water Molecules

  • Polar nature due to charge separation.

• Hydrogen Bonds

  • Attractive interactions between polar molecules.

Page 23-26: Properties of Water

• Cohesion and Adhesion

  • Cohesion: attraction between same molecules (surface tension).

  • Adhesion: attraction between different substances.

• Heat Capacity

  • Water can absorb/release energy with minimal temperature change.

Page 27-29: Mixtures and pH

• Types of Mixtures

  • Mixtures retain distinct identities; solutions are evenly distributed.

• Ionization of Water

  • Water can ionize into hydroxide (OH-) and hydrogen ions (H+).

• pH Scale

  • Indicates H+ concentration; critical for homeostasis.

Page 30-32: Carbon Compounds and Macromolecules

• Organic Chemistry

  • Study of carbon-containing compounds.

• Macromolecules

  • Formed via polymerization; four types: carbohydrates, lipids, nucleic acids, proteins.

Page 33-40: Macromolecule Types

• Carbohydrates

  • Sugars/starches; energy source and structure.

• Lipids

  • Fats/oils; energy storage and membrane formation.

• Nucleic Acids

  • RNA/DNA; hereditary information storage.

• Proteins

  • Enzymes and structural components; formed from amino acids.

Page 41-44: Protein Structure and Chemical Reactions

• Amino Acids

  • Building blocks of proteins; variable side chains.

• Peptide Bonds

  • Covalent bonds between amino acids.

• Chemical Reactions

  • Rearrangement of substances; bonds broken and formed.

Page 45-51: Energy in Reactions and Enzymes

• Chemical Equations

  • Represent reactions with reactants and products.

• Energy Dynamics

  • Energy is conserved; breaking bonds requires energy, forming bonds releases energy.

• Enzymes

  • Specific catalysts that lower activation energy and enhance reaction rates.