Notes

Hydrogen and Oxygen combined in the same proportion formed h20. John dalton a chemist and teacher wanted to know why? He published his first atomic theory in 1803. which includes all substance are made of atoms. Atoms are a small particle that cannot be created,divided, and destroyed. Atoms that have the same element are alike and atoms that of different elements are different. Atoms formed with other atoms make a new substance. by the late 1800s scientist agreed with daltons experiment and explain what they saw as dalton explanation. A greek philosopher name demetrius discovered that a particle can not be divided anymore or cut anymore he called it a atom. The word atom comes from a greek word atomos meaning cannot be divided. In 1897 a british scientist name J.J Thomson showed that dalton theory was was not quite right. Thomson discover that atoms have small particles inside the atom.. He also discovered that atoms can be separated by into smaller parts.He discovered a positively charge plate attracted the beam. Then he discovered that the beam had a negatively electric charges but since their are both opposites they attracted to each other. A negatively charge was a electron that thomson discovered. Also that it didnt prove that electrons was part of the atom. He made a guess saying that electrons was mixed with atoms. An example was called the plum-pudding that was popular in their time. But today Thomson example was called chocolate chip cookie the chocolate chip was the electron and the ice cream represent the rest of the atom.