The History of an Atom:
Researched by Conor MacGregor
• John Dalton proposed a model of the atom
• J.J. Thomson discovered the electron
• Ernest Rutherford had recently suggested the atom
had a miniature, dense nucleus surrounded by a
cloud of electrons.
• Max Planck established quantum theory
(wavelength and frequency of any wave were
related, and that the frequency was proportional to
the energy of the wave)
• Born and lived in Copenhagen, Denmark
• Full name; Niels Henrik David Bohr
• Won Nobel Prize for Physics in 1922
• Renown Physicist in his age
• Studied under Ernest Rutherford and
worked with J.J. Thomson
• Bohr proposed that when an electric current is passed through a pure elemental
gas, the gas gives off a certain type of unique color barcode that is called a line
• Bohr believed that the atom could only give off certain amounts of energy and
suggested that electrons occupy specific energy levels in the atom.
• In Bohr’s thinking, the energy levels can be considered concentric circles
around the nucleus and when an electron is stimulated it will jump to higher
energy levels, but it will eventually drop back down to the lowest energy level.
When an electron jumps it releases light and color which is what Bohr thought
created the line spectra
• Bohr also said that each level could only hold a certain number of electrons.
• Depiction of Bohr's Theory on the Atom
• Erwin Schrödinger forms new, more
accurate depiction of the atom
(Schrodinger’s Atom vs. Bohr’s Atom)
• James Chadwick discovers neutron
• 1. What did Bohr’s theory state about how
much energy an atom could give off?
• 2. What did Bohr’s theory state about the
movement of atoms?
• 3. How does Bohr’s theory support
• 4. How has quantum physics reshaped