HISTORY OF THE ATOM by Intza Arregi Arregi https://padlet.com/intzarregi/upmy70b3x6ochxoi Everything is made of atoms. en-us 2023-02-09 11:07:11 UTC 2025-12-08 11:51:27 UTC hello@padlet.com https://padlet.net/icons/png/2696.png DEMOCRITUS (440 BC) intzarregi https://padlet.com/intzarregi/upmy70b3x6ochxoi/wish/2474850787 He proposed that matter could not be divided into smaller pieces forever. He said that matter was made of small, hard particles that he called “atoms”. 


]]> 2023-02-09 11:20:06 UTC https://padlet.com/intzarregi/upmy70b3x6ochxoi/wish/2474850787 JOHN DALTON (1803) intzarregi https://padlet.com/intzarregi/upmy70b3x6ochxoi/wish/2474854336 He created the very first atomic theory. 
All substances are made of atoms. Atoms are small particles that cannot be created, divided, or destroyed. Atoms are invisible.
Atoms join together to make new substances (molecules).


]]> 2023-02-09 11:23:40 UTC https://padlet.com/intzarregi/upmy70b3x6ochxoi/wish/2474854336 JJ THOMSON (1897) intzarregi https://padlet.com/intzarregi/upmy70b3x6ochxoi/wish/2474856008

He discovered negatively charged particles inside the atom (electrons). 


]]> 2023-02-09 11:25:26 UTC https://padlet.com/intzarregi/upmy70b3x6ochxoi/wish/2474856008 ERNEST RUTHERFORD (1909-1911) intzarregi https://padlet.com/intzarregi/upmy70b3x6ochxoi/wish/2474858113

He proposed that in the center of the atom is positively charged part called the nucleus. He discovered the protons and nucleus. 


]]> 2023-02-09 11:27:31 UTC https://padlet.com/intzarregi/upmy70b3x6ochxoi/wish/2474858113 NIELS BOHR (1913) intzarregi https://padlet.com/intzarregi/upmy70b3x6ochxoi/wish/2483144061
He improved on Rutherford's model. He proposed that electrons move around the nucleus in certain paths called energy levels. 


]]> 2023-02-15 08:25:41 UTC https://padlet.com/intzarregi/upmy70b3x6ochxoi/wish/2483144061 SCHRODINGER AND HEISENBERG (1926) intzarregi https://padlet.com/intzarregi/upmy70b3x6ochxoi/wish/2483145692

He proposed that electrons do not travel in definite paths around the nucleus.


]]> 2023-02-15 08:27:17 UTC https://padlet.com/intzarregi/upmy70b3x6ochxoi/wish/2483145692