CHM1045 Spring 2025

Page 1: Classification Schemes of Matter (\text{(Chapter 1, Sections 1-3)})

Phases of Matter and Their Properties

  • Matter exists in three primary phases: solid, liquid, gas.

  • Solid: Has a definite shape and volume; particles are closely packed and vibrate in place.

  • Liquid: Has a definite volume but takes the shape of the container; particles are close together but can move past one another.

  • Gas: Has neither a definite shape nor volume; particles are far apart and move freely.

Chemical Change vs. Physical Change

  • Chemical Change: Involves a change in the chemical composition of substances (e.g., rusting of iron).

  • Physical Change: Alters the form or appearance of a material without changing its composition (e.g., melting ice).

Physical Properties

  • Properties can be categorized as extensive (depend on the amount of matter, e.g., mass, volume) or intensive (do not depend on the amount, e.g., density, boiling point).

Pure Substances vs. Mixtures

  • Pure Substance: Has a uniform composition and distinct properties (e.g., elements, compounds).

  • Mixture: Contains two or more substances that retain their individual properties (e.g., air, saltwater).

Elements vs. Compounds

  • Element: A pure substance made of only one type of atom (can be atomic or molecular; e.g., O, N2).

  • Compound: A substance formed from two or more elements chemically bonded together (e.g., H2O).

Observation vs. Inference

  • Observation: Information obtained through the senses; factual data.

  • Inference: Conclusion drawn from observations; may not be directly verifiable.

Page 2: Units and Unit Conversions (\text{(Chapter 1, Sections 4-6)})

Using Units Appropriately

  • Evaluate the suitability of specific units in problem-solving contexts.

Conversion Processes

  • Use a table of conversion factors to convert between different units (e.g., feet to meters).

  • Verify the appropriateness of an answer based on:

    • Magnitude/Scale

    • Sign

    • Units

    • Significant Figures

Scientific Notation

  • Identify convenient prefixes in scientific notation (e.g., centi (c), kilo (k), micro (μ), milli (m), nano (n)).

  • Convert units while considering these prefixes.

  • Round final answers to the appropriate number of significant figures.

Page 3: Isotopes and Atomic Mass, The Mole and Avogadro’s Number (\text{(Chapter 2, Sections 2-3)})

Structure of the Atom

  • Understand basic atomic structure: protons (+1), neutrons (0), electrons (-1).

  • Atomic Mass Unit (amu): A convenient unit for measuring mass at the subatomic level; protons and neutrons have approximately 1 amu.

Atomic Number and Mass Number

  • Define atomic number (Z) (number of protons), mass number (A) (number of protons + neutrons).

  • Identify these numbers on chemical symbols.

Periodic Table Insights

  • Elements are arranged by increasing atomic number.

  • Use the periodic table to deduce protons, neutrons, and electrons given an atomic symbol (e.g., 25Mg2+).

Isotopes

  • Define isotopes: atoms with the same atomic number but different mass number due to the varying number of neutrons.

  • Recognize isotopes through symbols (e.g., 37Cl vs. 35Cl) or conventional names (chlorine-35 vs. chlorine-37).

  • Describe natural abundances and stability differences among isotopes.

Average Atomic Mass

  • The mass listed on the periodic table represents the weighted average of all naturally occurring isotopes.

  • Predict how natural abundance affects the average atomic mass on the periodic table.

Avogadro’s Number

  • Define Avogadro’s number (NA) as 6.022 x 10^23.

  • Use NA to convert grams to amu (1 g = 1 mole of amu’s).

  • Distinguish average atomic mass (in amu) from average molar mass (in g).

  • Apply NA and atomic mass for conversions between grams, moles, and atoms.

Page 4: From Classical to Quantum Mechanics (\text{(Chapter 3, Section 1)})

Major Tenets of Quantum Mechanics

  • Wave-Particle Duality: Matter exhibits both wave-like and particle-like properties.

  • Quantization of Energy: Energy levels of electrons in an atom are quantized.

  • Inherent Uncertainty: There is an inherent uncertainty in measuring certain pairs of properties (e.g., position and momentum).

Wavelength and Frequency

  • Define and relate wavelength and frequency of light.

  • Convert between wavelength, frequency, and energy of light as needed.

Ground State vs. Excited States

  • Distinguish between ground state (lowest energy) and excited states (higher energy) of matter.

  • Explain how and why certain light is absorbed or emitted by matter.

Page 5: Bohr Model, Wavefunctions, and Quantum Numbers (\text{(Chapter 3, Sections 2-3)})

Assumptions of Bohr Model

  • Electrons orbit the nucleus at fixed radii (shells) and energy, transitioning between states by absorbing or emitting light.

Successes and Limitations

  • Successes include explaining hydrogen spectrum; limitations involve its inability to apply to multi-electron atoms.

Electronic Transition Calculations

  • Use Bohr levels to calculate photonic energy, wavelength, and frequency for transitions in hydrogen-like atoms.

Quantum Numbers

  • Define allowed values of quantum numbers: n (principal), l (azimuthal), ml (magnetic), and ms (spin).

Page 6: Orbitals and Electron Configurations (\text{(Chapter 3, Section 4)})

Quantum Numbers for Electrons

  • Use quantum numbers to describe shells, subshells, and orbitals.

  • Shorthand notation (e.g., "1s", "3p", "4d") to simplify descriptions.

Orbital Shapes

  • Identify the shapes of s, p, and d orbitals; recognize how these shapes influence electron configurations.

Principles Governing Electron Configurations

  • Aufbau Principle: Electrons occupy the lowest energy orbitals first.

  • Hund’s Rule: Electrons will fill degenerate orbitals singly before pairing up to minimize repulsion.

  • Pauli Exclusion Principle: No two electrons in an atom can have the same set of quantum numbers.

Ground State Electron Configuration

  • Predict the ground state electron configurations for elements and ions.

  • Define core and valence electrons; recognize their roles in chemical bonding and reactivity.

Unpaired Electrons

  • Analyze unpaired electrons in valence shells, which determine an atom’s chemical properties.

Page 7: Periodic Properties (\text{(Chapter 3, Section 5)})

Predicting Properties Based on Electron Configurations

  • Understand how electron configurations correlate to periodic properties including:

    • Atomic Radius: Generally increases down a group and decreases across a period.

    • Ionization Energy (IE): Energy required to remove an electron; generally increases across a period and decreases down a group.

    • Electron Affinity (EA): Energy change when an electron is added; generally increases across a period.

    • Electronegativity (EN): Tendency of an atom to attract electrons in a bond; trends follow those of ionization energy and atomic radius.

Position of Elements

  • Recognize the general positions of metals, nonmetals, and metalloids on the Periodic Table.