Download Chapter 2: Data Analysis

Unit 3 – Electron Configurations
Part B: Bohr’s Model of Hydrogen
"Every word I utter is to be understood not as an
affirmation but as a question."
What have we learned so far?
Discharging Tubes
The Flame Test
The light coming out of the excited
atomic entities is very specific to
particular element!
Results are quite reproducible.
Conclusions:
 Electromagnetic radiations (lights) coming out
or being absorbed by atoms indicate that there
are very specific energy changes within the
atomic entities (atoms and ions).
 No nuclear changes have ever been observed
indicate that the energy changes have to come
from electrons surrounding the nucleus.
How come?
 Classic Model:
 Problems with the classic model:
Niels Bohr
(1885 – 1962)
Bohr’s Model of Hydrogen Atom
Increasing energy
Fifth
Fourth
Third
Second
First
Nucleus
 Further away from the
nucleus means more
energy.
 There is no “in
between” energy
 Energy Levels
Bohr’s Model of Hydrogen Atom
quantum – quantity of energy gained or lost by an atom when
electrons are excited
photon – a quantum of light
ground state – lowest energy level of an atom
excited state – a heightened state of energy in an atom
Electrons of hydrogen circle the nucleus in orbits
1. orbits have a fixed amount of energy in the ground state.
2. orbits are a fixed distance from the nucleus.
3. orbits furthest from the nucleus have the greatest energy.
Bohr’s Model of Hydrogen Atom
SUPPLIMENTARY WEBSITES:
http://venables.asu.edu/quant/Dinesh
/Bohratom2.html
http://dl.clackamas.edu/ch104/lesso
n5bohrmodel.html
Bohr’s Model of Hydrogen Atom
Bohr’s Model of Hydrogen Atom
Bohr’s Model of Hydrogen Atom
Bohr’s Model of Hydrogen Atom