1. Atomic Theory Song

2. Matter & The Atomic Model A Timeline of Discovery

3. Matter
The term matter describes all of the physical substances around us: your table, your body, a pencil, water, and so forth
Defined as anything that has mass and takes up space (has volume)
Includes all things that can be seen, tasted, smelled, or touched
Does not include heat, sound, or light

4. Matter is made of atoms

5. The Atomic Model A Timeline of Discovery
Models are often used for things that are too small or too large to be observed or that are too difficult to be understood easily
In the case of atoms, scientists use large models to explain something that is very small
Models of the atom were used to explain data or facts that were gathered experimentally.
So, these models are also theories

6. Early Models of the Atom Democritus Greek Philosopher( 470-380B.C)
Universe was made of empty space and tiny bits of stuff
Called these tiny bits of small, hard particles he called “ atomos”
Atoms could not be divided into smaller pieces

7. Early Models of the Atom Dalton 1808
Created the first Atomic Theory.
He viewed atoms as tiny solid balls.
His theory had 4 statements.

8. Dalton’s Theory All elements are composed of indivisible particles.
Atoms of the same element are the same
Atoms of different elements are different.
Compounds consisted of atoms of different elements combined together

9. Early Models of the Atom JJ Thompson 1897
He was the first scientist to show that atoms were made of even smaller things.

10. Early Models of the Atom Thompson
Plum pudding model
Atom made of a positively charged material with the negatively charged electrons scattered through it.

11. JJ Thompson’s Ideas

12. Cathode Ray Tube Experiment

13. Early Models of the Atom Rutherford 1911
Discovered protons and nucleus

14. Early Models of the Atom Rutherford
Mostly empty space
Small, positive nucleus
Contained protons
Negative electrons scattered around the outside

15. Rutherford’s Gold Foil Experiment

16. Early Models of the Atom Bohr 1913
Electrons move in around the nucleus in specific layers or shells
Every atom has a specific number of electron shells.

17. Early Models of the Atom Chadwick 1932
Discovered the neutron

18. Ernst Schrödinger 1887-1961 Werner Heisenberg 1901-1976
Quantum Mechanical Model 1926
Electrons are in probability zones called “orbitals”, not orbits and the location cannot be pinpointed
Electrons are particles and waves at the same time
Developed quantum numbers based on theories of Einstein and Planck

19. Orbitals

20. Dmitri Mendeleev
    In the late 1860s, Mendeleev began working on his great achievement: the periodic table of the elements. By arranging all of the 63 elements then known by their atomic weights, he managed to organize them into groups possessing similar properties. Where a gap existed in the table, he predicted a new element would one day be found and deduced its properties

21. Henry Moseley 1913
When atoms were arranged according to increasing atomic number, the few problems with Mendeleev's periodic table had disappeared. Because of Moseley's work, the modern periodic table is based on the atomic numbers of the elements.