Chemistry Chapter: Atomic Structure & Bonding

Atomic Structure

• Atoms are the fundamental building blocks of matter.
• Atoms consist of a nucleus, containing protons and neutrons, and orbiting electrons.
• Protons have a positive charge, electrons have a negative charge, and neutrons are neutral.
• The number of protons in an atom's nucleus defines the atom's atomic number and element.
• Atomic mass is the sum of protons and neutrons in an atom.
• Electrons occupy specific energy levels (shells) around the nucleus.
• Each energy level can hold a specific number of electrons (2n²).
• Valence electrons are the electrons in the outermost energy level and are involved in chemical bonding.

Chemical Bonding

• Chemical bonds hold atoms together to form molecules.
• Ionic bonds involve the transfer of electrons between atoms, forming ions with opposite charges that attract.
• Covalent bonds involve the sharing of electrons between atoms.
• Metallic bonds involve the sharing of delocalized electrons between metal atoms.
• Hydrogen bonds are a special type of dipole-dipole interaction between a hydrogen atom attached to a highly electronegative atom (e.g., oxygen, nitrogen, or fluorine) and another electronegative atom.
• Intermolecular forces are forces of attraction between molecules. These include:
  • van der Waals forces (weakest)
  • dipole-dipole forces (intermediate)
  • hydrogen bonds (strongest)
• The strength of intermolecular forces affects the physical properties of substances, like boiling point and melting point.

States of Matter

• Matter exists in three primary states: solid, liquid, and gas.
• Solids have a fixed shape and volume due to strong intermolecular forces.
• Liquids have a fixed volume but take the shape of their container due to weaker intermolecular forces.
• Gases have neither a fixed shape nor a fixed volume due to extremely weak (or no) intermolecular forces.
• Changes between states of matter involve energy transfer:
  • Melting (solid to liquid)
  • Freezing (liquid to solid)
  • Vaporization (liquid to gas)
  • Condensation (gas to liquid)
  • Sublimation (solid to gas)
  • Deposition (gas to solid)

Chemical Reactions

• Chemical reactions involve the rearrangement of atoms to form new substances.
• Reactants are the substances that undergo change.
• Products are the substances formed as a result of the reaction.
• Chemical equations represent chemical reactions using chemical formulas and coefficients to indicate the relative amounts of reactants and products.
• Stoichiometry is the calculation of reactants and products in chemical reactions using balanced chemical equations.
• Several driving forces for chemical reactions exist including:
  • Formation of a solid (precipitation)
  • Formation of water
  • Transfer of electrons (redox reactions)

Solutions

• Solutions are homogeneous mixtures of two or more substances.
• The solute is the substance dissolved in the solvent.
• The solvent is the substance that dissolves the solute.
• Concentration refers to the amount of solute in a given amount of solution.
• Common units of concentration include molarity (mol/L), and percent by mass.
• Properties of solutions:
  • Solubility is the maximum amount of solute that can dissolve in a given amount of solvent at a specific temperature and pressure.
  • Factors affecting solubility include temperature and pressure.

Acids and Bases

• Acids are substances that release hydrogen ions (H+) in water.
• Bases are substances that release hydroxide ions (OH-) in water.
• The pH scale measures the acidity or basicity of a solution.
• A pH of 7 is neutral.
• pH values below 7 are acidic, and values above 7 are basic.
• Strong acids and bases completely dissociate in water.
• Weak acids and bases partially dissociate in water.
• Neutralization reactions occur when acids and bases react to form a salt and water.

Periodic Table

• The periodic table organizes elements based on their atomic structure (primarily electron configuration).
• Elements in the same column (group) have similar chemical properties.
• Elements in the same row (period) have increasing atomic numbers and varying properties.
• Metals, nonmetals, and metalloids are categorized by their properties.
• Trends in properties, such as electronegativity, ionization energy, and atomic radius, are observed across periods and groups.

Kinetics

• Kinetics studies the rate of chemical reactions.
• Reaction rates depend on factors such as temperature, concentration, surface area, and catalysts.
• Collision theory explains how the rate of a reaction depends on the frequency and energy of collisions between reactant particles.
• Activation energy is the minimum energy required for a reaction to occur.
• Catalysts increase the rate of a reaction by lowering the activation energy without being consumed in the process.

Explore the core concepts of atomic structure and chemical bonding in this chemistry quiz. Understand the roles of protons, neutrons, and electrons, as well as the differences between ionic, covalent, and metallic bonds. Test your knowledge on how these concepts are fundamental to the formation of molecules.