1. Atoms (12 lessons)

Concepts

  • Matter is made of atoms.  Atoms consist of a dense nucleus containing protons (p+) and neutrons (n), and the electrons (e-) that “orbit” this nucleus.
  • According to the Bohr model of the atom, electrons exist in discrete “orbits” (energy levels) around the nucleus of an atom.  Each energy level can contain a maximum number of electrons (2, 8, 8, 18, 18, 32, 32,…).  While current quantum-mechanical models of the atom are more accurate, the Bohr model is good enough to explain the phenomena we will observe in this course.
  • Chemical properties of matter can be mostly explained by interactions between electrons and protons.  The force a proton exerts on an electron is weaker when the particles are farther apart.  Inner electrons also “shield” outer electrons from the nucleus, resulting in a weaker attraction between the nucleus and the electron.  These two factors can be summarized by the concept of “electronegativity” – a measure of the ability of an atom to attract an electron in a chemical reaction.
  • Each row of the periodic table contains a series of elements with the same number of core electrons.  Each column of the periodic table contains a family of elements with the same number of outer electrons.
  • Electronegativity is highest in the top-right corner of the periodic table.  For the same reason, the largest atoms are in the bottom-left corner of the table.  Low electronegativity = metallic.

Skills

Quiz 1a

  • Identify the relative mass and charge of protons, neutrons, and electrons.
  • Calculate the mass and charge of an atom based on its constituent particles.
  • Draw the Bohr diagram of an atom that may be a strange isotope or ionized.

Quiz 1b

  • Perform calculations involving scientific notation, to the correct level of precision.
  • Calculate the effective nuclear charge of an atom, and draw conclusions about its electronegativity.
  • Identify trends in atomic mass, volume, electronegativity, radioactivity, and reactivity in the periodic table.

Homework

Quiz 1a

Quiz 1b

Projects & Labs

Quiz 1a

  • Point charge simulation

Quiz 1b

Assessment

  • Quiz 1a: Electrostatic force, subatomic particles, Bohr model
  • Quiz 1b: Electronegativity; periodic table
  • Test 1: Atoms