Unit 1 (Atomic Structure and Periodicity)

• What are the most common types of interactions among particles?

  Electrostatic, metallic bonding, London dispersion, dipole-dipole, hydrogen bonding, Coulombic attraction, ion-dipole, dipole-induced dipole, and ion-induced dipole.
• Why are atomic masses listed on the periodic table averages?

  Because they are based on the number of isotopes and their relative percent abundances.
• How can a mass spectrometer be used in chemistry?

  To determine accurate mass values of atoms and their relative abundances.
• What are crystalline solids characterized by?

  Ordered structures and unit cells.
• What are the three main types of atomic crystalline solids?

  • Metallic: Held together by metallic bonds, high melting points, good conductors, malleable and ductile.
  • Covalent-Network: Atoms connected by covalent bonds, high melting points, poor conductors.
  • Group 8A: Solidified noble gases held by London dispersion forces.
• Why are transition elements considered the hardest and strongest elements?

  Because they have more delocalized electrons.
• What are the two types of alloys discussed?

  • Substitutional Alloy: Components have similar atomic radii and can substitute into the crystal lattice.
  • Interstitial Alloy: Smaller elements fit into the interstitial spaces of larger elements.
• How do the forces of attraction differ between solids and liquids/gases?

  The forces of attraction for liquids and gases are usually weaker than those of solids.
• What does the quantum mechanical model of the atom describe?

  • Energy levels as regions of high probability for finding electrons.
  • Each energy level consists of sublevels and atomic orbitals with specific shapes.
• What are the three rules governing the filling of atomic orbitals?

  The Pauli exclusion principle, the aufbau principle, and Hund’s rule.
• What does the Pauli exclusion principle state?

  Only two electrons can occupy an atomic orbital and they must have opposite spins.
• What does the aufbau principle state?

  Electrons enter orbitals of lowest energy first.
• What does Hund’s rule state?

  When electrons occupy orbitals of equal energy, one electron occupies each orbital until all orbitals contain one electron with parallel spins.
• How can you derive electron configurations from the periodic table?

  By examining the element’s position and recording each filled sublevel.
• What happens to electrons when they absorb energy?

  They move to an excited state.
• What occurs when an electron falls back to its ground state?

  It emits energy in the form of colored light.
• What does isoelectronic mean?


  Having the same electron configuration.
• What are the exceptions to electron configurations in the lanthanide and actinide series?

  They involve slight deviations from the aufbau principle.
• What is paramagnetism?


  Attraction to a magnetic field due to unpaired electrons.
• What is diamagnetism?


  Repulsion from a magnetic field due to paired electrons.
• How can you predict whether an element is paramagnetic or diamagnetic?

  By examining the electron configuration for unpaired or paired electrons.
• What is the unit of frequency?

  Hertz (Hz)
• How is wavelength typically measured?

  In meters (m) or nanometers (nm)
• What is the photoelectric effect?

  • Ejection of electrons from metal surfaces when exposed to light of certain frequencies
  • Requires specific frequency and corresponding energy
• How does photoelectron spectroscopy (PES) contribute to our understanding of electron arrangement?

  • Utilizes photoelectric effect data
  • Helps determine electron configuration around a nucleus
• What does Beer’s Law calculate?

  The concentration of a solution from absorbance measurements
• How do you determine the concentration of an unknown solution using Beer’s Law?

  1. Create a line of best fit between known concentrations and absorbance readings.
  2. Use the line to find the concentration of the unknown.
• What is periodicity in the context of the periodic table?

  It is the periodic recurrence of properties among elements arranged by increasing atomic number.
• What are the three basic rules that explain periodic trends?

  1. Electrons are attracted to protons in the nucleus.
  2. Electrons are repelled by other electrons.
  3. Completed p sublevels are stable.
• What is nuclear charge?

  Nuclear charge is the attraction between electrons and protons in the nucleus.
• What is the shielding effect?


  The tendency of inner electrons to block the attraction of the nucleus for valence electrons.
• How do nuclear charge and shielding effect influence periodic trends?

  Nuclear charge influences period trends, while shielding effect influences group trends.
• What does Coulomb’s Law describe?

  The attraction and repulsion between charged particles.
• What conclusions can be drawn from Coulomb’s Law regarding charged particles?

  1. Like charges have positive potential energy that decreases with distance.
  2. Opposite charges have negative potential energy that becomes more negative as they get closer.
  3. Interaction magnitude increases with charge magnitude.
• What is effective nuclear charge?

  Effective nuclear charge accounts for the shielding effect that reduces the nuclear charge felt by valence electrons.
• How is atomic radius defined?

  The atomic radius is half the distance between two nuclei in adjacent atoms.
• How does atomic radius change across the periodic table?

  The atomic radius decreases as you move across the periodic table.
• How does atomic radius change down a group in the periodic table?

  The atomic radius increases as you move down a group.
• What is ionization energy?


  Ionization energy is the energy required to remove an electron from an atom.
• How does the ionic radius of cations compare to their atomic radius?

  The ionic radius of cations is smaller than their atomic radius.