The Nature of the Atom

Student Learning Objectives
Lessons / Lecture Notes
Important Equations
Example Problems
Applets and Animations

Student Learning Objectives

Lessons / Lecture Notes

PY106 Notes from Boston University (algebra-based):

Introductory physics notes from University of Winnipeg (algebra-based):

HyperPhysics (calculus-based)

Important Equations


Example Problems

Problem 1
In the line spectrum of atomic hydrogen there is also a group of lines known as the Pfund series.  These lines are produced when electrons, excited to high energy levels, make transitions to the n = 5 level.  Determine (a) the longest wavelengths and (b) the shortest wavelengths in this series. (Solutions)

Problem 2
(a) The electron in a hydrogen atom is in the first excited state, when the electron acquires an additional 2.86 eV of energy. What is the quantum number n of the state into which the electron moves? (Solutions)

(b) A laser is used in eye surgery to weld a detached retina back into place. The wavelength of the laser beam is 514 nm, and the power is 1.5 W. During surgery, the laser beam is turned on for 0.050 s. During this time, how many photons are emitted by the laser? (Solutions)

Applets and Animations

Rutherford Scattering

How did Rutherford figure out the structure of the atomic nucleus without looking at it? Simulate the famous experiment in which he disproved the Plum Pudding model of the atom by observing alpha particles bouncing off atoms and determining that they must have a small core.

Bohr Model of Hydrogen

The photon excitation and photon emission of the electron in a Hydrogen atom as described by the Bohr model.

Models of the Hydrogen Atom

How did scientists figure out the structure of atoms without looking at them? Try out different models by shooting photons and alpha particles at the atom. Check how the prediction of the model matches the experimental results.

Interaction of X-Rays with Matter

Illustrating the 3 principle modes by which X-rays interact with matter.

Neon Lights and Discharge Lamps

Produce light by bombarding atoms with electrons. See how the characteristic spectra of different elements are produced, and configure your own element's energy states to produce light of different colors.

Laser Animation
This applet illustrates a schematic operation of a laser. The  yellow photons  represent the pumping radiation. The group of red photons is the coherent laser beam. The balls mark the atoms making transitions between three energy levels.

Create a laser by pumping the chamber with a photon beam. Manage the energy states of the laser's atoms to control its output.

Simplified MRI

Is it a tumor? Magnetic Resonance Imaging (MRI) can tell. Your head is full of tiny radio transmitters (the nuclear spins of the hydrogen nuclei of your water molecules). In an MRI unit, these little radios can be made to broadcast their positions, giving a detailed picture of the inside of your head.

Bells Theorem Based on an analysis by Mermin, this animation explores correlation measurements of entangled pairs.
Eigenstate Superposition

The Eigenstate Superposition model illustrates the fundamental building blocks of one-dimensional quantum mechanics, the energy eigenfunctions  ψn(x) and energy eigenvalues En.

Free Particle Energy Eigenstates

The Free Particle Energy Eigenstates model shows the time evolution of a superpostion of free particle energy eigenstates.  A table shows the energy, momentum, and amplitude of each eigenstate.

Quantum Mechanical Measurement

The QM Measurement program displays the time evolution of the position-space wave function and can be used to simulate the quantum-mechanical measurements of energy, position, and/or momentum.  The default wave function is an equal-mix four-state superposition in the infinite square well.

Barrier Scattering

The Barrier Scattering model shows a quantum mechanical experiment in which an incident wave (particle) traveling from the left is transmitted and reflected from a potential step at x=0.