Upload
phungtu
View
220
Download
0
Embed Size (px)
Citation preview
THINK PAIR SHARE
On your own, draw the model of a hydrogen atom. Can you draw an oxygen atom using the same model? Don’t forget to label your diagrams.
Pair up with two of your classmates and share your models of hydrogen and oxygen. Did you all come up with the same picture? Or is it different? Come up with one model of each hydrogen and oxygen as a group.
Share your model with the whole class!
BOHR MODEL OF AN ATOM
P = 1N = 0
Hydrogen Atom
Nucleus (holds protons and neutrons)
Electron Shell (holds electrons)
DALTON’S ATOMIC MODEL Postulate 1: All matter is made up of small particles called atoms.
Postulate 2: An element consists of an atom of one type only.
Postulate 3: Compounds consist of atoms of more than one element.
Postulate 4: Atoms can not be created or destroyed in a chemical reaction.
Element
Compound
THOMSON’S ATOMIC MODEL
Thomson discovered the electron in 1897.
He said that negatively charged particles called electrons are submerged in a positive region.
To explain his model, he compared it to plum-pudding where the pudding is the positive region and electrons are raisins submerged into in a positive region.
Thomson called his model the “plum-pudding” model.
RUTHERFORD’S SCATTERING EXPERIMENT
Source of 𝛂 - particles
Detector
Gold-Foil
𝛂 - particle is He2+ ion
According to Thomson’s model, the beam of alpha particles would have gone straight through the gold atoms with little to no deflection.
The result of scattering experiment was far from what was expected. Most of the alpha particles went straight through, but some were deflected. This proved that the atom had a positive core (nucleus).
JAMES CHADWICK
In 1932, it was discovered by Chadwick that the nucleus is composed of neutronsand protons.
Neutrons have a charge of 0 and protons have a charge of +1