HISTORY-OF-ATOM pptx- Models of Atoms and Scientists Involve.

HISTORY-OF-ATOM pptx- Models of Atoms and Scientists Involve.

1. History of the Atom

2. OBJECTIVES Recall the characteristics of particles in different states of matter.

3. OBJECTIVES Define an atom and describe the contributions of early Greek philosophers.

4. REVIEW!

5. Label the diagram using the words in the word-bank. Liquid melting gas freezing Boiling solid condensing

6. ANSWER

7. Activity: “Cut it until you Make it”

8. Materials: scissors and colored 11”x1” piece of paper

9. Instructions: Fold the paper in half then cut along the centerfold. Take half of the paper, fold it again in half and then cut it again along the fold. Do this repeatedly until it is difficult to cut.

10. How can you describe the last piece of paper you are holding?

11. How can you compare it to the original size of the paper?

12. Unlocking Content Vocabulary

13. Atom- basic unit of matter.

14. Nucleus- center of the atom

15. Subatomic- smaller than the atom.

16. Electrons- negatively charged subatomic particles

17. Protons – positively charged subatomic particles

18. Neutrons – neutral subatomic particles.

19. All atom share the same basic structure. During the past 200 years, scientists have proposed different models of an atom. Let’s explore the discovery of different atomic structures

20. For Democritus , atoms are indestructible and completely full, so there is no empty space. Both Leucippus and Democritus had the idea that there are many different kinds of atoms and each of them had specific shape and size and that all atoms move randomly around in space..

21. Democritus believed that any piece of matter can be divided and subdivided into very small particles but that this process ended at some point when a piece is reached that could not be further divided.

22. He called this particle, atomos , a Greek word which means indivisible particle. Democritus’ ideas about the atom were later challenged by other Greek philosophers, most strongly by Aristotle.

23. Aside from the lack of experimental evidence , Aristotle , a famous and influential Greek Philosopher, played a major role why Democritus’ idea was disregarded. He believed that matter is infinitely divisible and there is no such thing as void. Democritus’ idea was also against Christian beliefs.

24. .

25. Based on experiments, Dalton developed a theory of structure of matter. He wrote in his 1st theory that: All elements are composed of tiny indivisible particles called atoms. Atoms of each element are exactly alike and have the same mass. An atom of one element cannot be charged into an atom of a different element. Atoms of different elements can join to form compounds.

26. Dalton was wrong about all elements of the same type being identical. Atoms of the same elements can have different numbers of NEUTRONS. Thus, different mass numbers. These are called ISOTOPES.

27. Dalton thought that atoms were like smooth, hard balls that could not be broken into smaller pieces.

28. J.J THOMSON ATOMIC THEORY

29. Ernest Rutherford’s Atomic Theory

30. Activity 1: The Atom: from Greeks to Dalton

31. 1.Draw a representation of Democritus’ idea of an atom.

32. 2.Why do you think Democritus’ idea of the atom was disregarded? Who influenced this movement?

33. What term means "indivisible"? a. Atom b. Proton c. Electron d. Neutron

34. Which philosopher proposed the idea of “atomos”? a. Aristotle b. Socrates c. Democritus d. Dalton

35. He discovered that electrons exist in several distinct layers or levels “energy level”. Dalton Rutherford Bohr Chadwick