Neils Bohr
1913 model
His "Galaxy" Theory
Bohr theorized that electrons revolved around the nucleus on invisible rings in certain patterns. This is similar to the way that planets revolve around the sun in our galaxy. The electrons went a 2, 8, ,8, 18, 32 structure.
What Was Wrong With The Model?
In the 1920's, Werner Heisenberg discovered that Bohr's model was incorrect. Electrons didn't orbit the nucleus in well defined circular orbits. Also, the correct structure is 2, 8, 18, then 32.
How to Make the Model
Calcium
Take the atomic number of the element. In this case, calcium's atomic number is 20.
Neils Bohr
Bohr Model
- Put only 2 electrons in the first ring
- Put 8 in the second ring
- Put 8 in the third
- Put 2 in the fourth