Unit 3

In Unit 3, you will (mostly) be able to put away your calculators, especially in comparison with the previous unit.  Unit 3 is largely conceptual.  It will pick up where we left off in our look at the atom back in the first unit the second week of the semester and focus on the electrons, what they are doing in the atom, and how they determine the chemistry of the various elements.

In the first topic, Electronic Structure of Atoms & Periodic Properties of Elements, you will learn about the historical development and current understanding of the location and movement of electrons within the atom and how that impacts the properties of the various elements.

Next, we will shift our attention to compounds and molecules.  In our look at Basic Concepts of Chemical Bonding & Molecular Geometry, you will examine how the material just learned in the previous topic affects how atoms combine to make molecules or (in the case of ionic compounds) repeating crystal structures and therefore elements combine to make compounds.

Unit 3 Learning Objectives

Electronic Structure of Atoms & Periodic Properties of Elements

  1. Describe the wave nature of electromagnetic radiation and list the various types of electromagnetic radiation by wavelength and frequency.
  2. Knowing the speed of light, convert between wavelength and frequency of electromagnetic radiation.
  3. Describe the essential features of Planck’s quantum theory and interconvert among wavelength, frequency and energy of a quantum.
  4. Using the de Broglie equation, calculate particle wavelength given particle mass and velocity.
  5. Explain the origin of line spectra.
  6. Describe the Bohr model of the hydrogen atom.
  7. Calculate the energy differences between any two electronic states of a hydrogen atom and the wavelength of frequency of the photon involved in the transition.
  8. Explain the significance of the wave function and the square of the wave function of an electron as they pertain to the orbital, electron density and probability.
  9. Describe the Heisenberg uncertainty principle.
  10. Explain the physical significance of each of the quantum numbers and know the restrictions on possible values.
  11. Describe the shapes and orientations of s and p atomic orbitals.
  12. Use the Aufbau principle, the Pauli exclusion principle and Hund’s rule to predict how electrons will fill orbitals in an atom.
  13. Give the electronic configuration of selected atoms.
  14. Predict and explain the relative sizes of atoms based on their positions in the periodic table.
  15. Predict the relationship between the size of a neutral atom and its ions.
  16. Define ionization energy and electron affinity.
  17. Predict and explain the ionization energies of atoms based on their positions in the periodic table.
  18. Describe the periodic trends in metallic and nonmetallic character.

Basic Concepts of Chemical Bonding & Molecular Geometry and Bonding Theory

  1. Define the terms: ionic bonding, covalent bonding, bond length, bond strength, bond order, dipole moment, and lattice energy.
  2. Write the electron configuration of ions of the s- and p- block elements.
  3. Define electronegativity and relate the electronegativity of an atom to its position in the periodic table.
  4. Classify a bond as nonpolar covalent, polar covalent, or ionic based on the differences in electronegativity.
  5. Write Lewis Dot Structures of ionic and covalent compounds and polyatomic ions.
  6. Predict relative bond polarities.
  7. Write the electronic configurations of ions of s- and p- block elements.
  8. Recognize examples of molecules on ions that are exceptions to the octet rule: less than an octet, expanded octet and odd number of electrons.
  9. Define resonance (delocalized bonding), recognize when resonance can exist and draw all possible resonance forms of a particular compound or ion.
  10. Calculate formal charges of atoms in a molecule or ion.
  11. Given a table of bond energies, estimate the enthalpy change for a specified reaction.
  12. Define electronegativity and relate the electronegativity of an atom to its position in the periodic table.
  13. Relate bond order to bond length and bond strength.
  14. Relate the number of electron pairs in the valence shell of an atom in a molecule to their geometrical arrangement of the pairs around the atom.
  15. Using Valence Sheel Electron Pair Repulsion (VSEPR) Theory predict the geometry of a molecule or polyatomic ion.
  16. Explain how nonbonding electron pairs compress the angles between bonding pairs.
  17. Using dot structures, determine the number of sigma and/or pi bonds in a molecule or polyatomic ion given the chemical formula.
  18. Predict whether or not a molecule is polar.
  19. Explain the concept of hybrid orbitals (sp, sp2, sp3, dsp3, d2sp3) and their relationship to geometrical structures.
  20. Based on the Lewis Dot Structure, describe the hybridization, bonding and geometry about the central atom of an ion or molecule.
  21. Explain the concept of delocalization in pi bonds.

Unit 3 Topics

Study these in order:

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