Download Atomic Structure Timeline Notes

Name __________________________________________________________ Date ___________ Period ________
Atomic Structure Timeline Notes
400 B.C. ___________________________________
Proposed that ___________________ was composed of tiny indivisible particles called
_____________________.
1807 _____________________________ _________________________________
A British schoolteacher who based his theory on others experiment. Scientist used
the __________________________ __________________ __________________
and discovered that the atom was a _____________________________, solid
________________________.
Dalton’s Four Postulate
1. Elements are composed of small indivisible particles called __________________.
2. Atoms of the same element are __________________________. Atoms of
different elements are ________________________________.
3. Atoms of different elements combine together in simple proportions to create a
______________________________________.
4. In a chemical reaction, atoms are __________________________, but not
______________________________________.
1896 ______________________________ ____________________________
Discovered radioactivity by spontaneous emission of radiation from the
_______________________. He discovered that there were three types of emission
____________________, _________________________, _____________________
1903 ____ ______ ______________________
Using the cathode ray tube experiment he used a beam to discover that there were
negative particles. Therefore, discovering __________________________. Which are
negatively charges particles with in the atom. He used the ____________________
______________________ model to explain his discovery. Plum-pudding Model has a
positive sphere (pudding) with _______________________ electrons (plums)
dispersed throughout.
1911 ___________________________ ___________________________________
Using the Gold Foil experiment he discovered that the _________________________
had a dense, _____________________ charge in the center of the atom. He used the
____________________________ model to explain his discovery.
1913 _____________________________ ____________________________
Scientist used the bright-line spectrum to explain the presence of specific colors in
the hydrogen spectrum. Based on the _______________________
______________________ electrons can only exist in specific energy states. He used
the ________________________ Model to explain his discovery.
The Planetary Model showed how the electrons moved in circular orbits within
specific energy levels.
1926 ______________________ _______________________________________
Scientist used Quantum mechanics to discover that the electrons can only exist in
specific energy states. Using the _______________________
______________________ model he used dots to represent the probability of finding
electron (orbitals) not actual electrons.
1932 __________________________ _______________________________
Scientist discovered that the _________________________ was a neutral particle in
the nucleus of an atom. Joliot-Curie used his experiment and based his theory on the
evidence of James Chadwick. Chadwick revised Rutherford’s model and called his
model the ___________________________ Model to explain his discovery.