Part I: PhET simulation of different theories of atoms Part II: Analyze Spectroscope Data

Niels Bohr Born in Denmark ( ) Bohr received his poorest marks in composition and struggled with writing during his entire life. In fact, he wrote so poorly that he was forced to dictate his PhD thesis to his mother. He constructed a quantum model for the hydrogen atoms by the time he was 27 years old and won the Nobel prize in physics in 1922.

Bohr’s Model 1.e- orbit the nucleus at only certain energy levels or are “quantized”. 2.Energy of an e- in the nth orbit of H atom is E n = - Rhc/n 2 3.R=Rydberg constant, x 10 7 /m 4.The radius of orbits is called the Principle Quantum Number 5.Atom in ground state is e- in lowest energy level. (more energy is less negative) (lowest energy is highest negative number)

Absorption of energy when an atom moves to an excited energy level.  E = E final – E initial  E = E 2 – E 1 = (-Rhc/2 2 ) – (- Rhc/1 2 ) = ¾(Rhc) = 984 kJ/mol of H atoms

Some of the electronic transitions that can occur in an excited H atom. Ionization energy the energy to remove the e- from the atom n = ∞ and can be measured in the laboratory.