1. Atomic Theory and Developing an Atomic Model

2. Learning Target
I CAN describe the experimental design and explain the conclusions used in the development of modern and atomic theory, including Dalton’s Postulates, Thomson’s discovery of electron properties, Rutherford’s nuclear atom, and Bohr’s nuclear atom

3. Criteria for Success
I CAN explain the contributions of Dalton, Thomson, Rutherford, and Bohr to the modern atomic theory
I CAN describe the models of the atom that Dalton, Thomson, Rutherford, and Bohr proposed.
I CAN identify which experiment and results lead to which discovery for Dalton, Thomson, Rutherford, and Bohr.

4. Atomic Theory and Developing an Atomic Model
A. Atomic Theory: __________ is anything that has mass and takes up space.
1. All matter is made up of __________
matter
atoms

5. Atomic Theory and Developing an Atomic Model
1. Democritus (400 BCE)
All matter is made up of extremely small, solid, ___________ particles called atoms
indivisible

6. Atomic Theory and Developing an Atomic Model
2. John Dalton (1808)
Dalton’s Atomic Theory (The Four Postulates)
1. All elements are made up of tiny, indivisible particles called atoms, which ___________ be broken down into smaller parts
2. Atoms of the ________ element are identical (same mass, same properties); different elements are different.
cannot
same

7. Atomic Theory and Developing an Atomic Model
2. John Dalton (1808)
Dalton’s Atomic Theory (The Four Postulates)
3. Atoms of different elements _______ combine together in whole-number ratios to form compounds.
4. During chemical reactions, atoms are rearranged, but atoms of one element ___________ be changed into atoms of a different element
can
cannot

8. Atomic Theory and Developing an Atomic Model
3. Joseph John (JJ) Thomson (1897)
____________________experiment
Cathode ray

9. Atomic Theory and Developing an Atomic Model
3. JJ Thomson (1897)
Atoms actually contain small, negatively charged particles (________________)
Plum-pudding model
electrons
Which of Dalton’s postulates did Thomson disprove, and why?

10. Atomic Theory and Developing an Atomic Model
4. Ernest Rutherford (1911)
____________________ experiment
Gold foil

11. Atomic Theory and Developing an Atomic Model
Ernest Rutherford (1911)
Atoms consist of a very small, positively charged region called the ___________, surrounded by small, negatively charged particles
nucleus

12. Atomic Theory and Developing an Atomic Model
5. Niels Bohr (1913)
___________________________ model
Electrons exist in specific ____________
Studied hydrogen emission spectrum
Bohr / Planetary
orbits

13. Atomic Theory and Developing an Atomic Model
6. Louis DeBroglie, Werner Heisenberg, and Erwin Schrodinger (early 1900s)
Elaborated on Bohr’s orbits
Described the region in which the negative particles existed as ________________
orbitals

14. Atomic Theory and Developing an Atomic Model