1. The Atom

2. What are Atoms?
Atoms are the basic building blocks of matter that make up everyday objects. A desk, the air, even your body is made up of millions of atoms.
There are 90 naturally occurring kinds of atoms and 25 more that are man-made.
The Periodic Table of the Elements list these atoms – from smallest to largest.

4. The idea of the atom was first devised in 530 B. C
The idea of the atom was first devised in 530 B.C. by a Greek named Democritus.
He was born about 460 B.C. and died at more than a hundred years of age. It is said that from then on he spent his days and nights in caverns and sepulchers, and in order to master his intellectual faculties, he blinded himself with burning glass. This story, however, is discredited by the writers who say he wrote books and dissected animals, neither of which could be done well without eyes.

5. Science TV
Atom - Democritus

6. Review of Atomic Structure

7. The nucleus was discovered in 1911 by
Ernest Rutherford. Here’s how he did it:
Atom – Rutherfords Experiment

8. Let’s take a look again at that nucleus…

9. Science TV
Atom - Nucleus

10. The nucleus is the massive center of the atom
The nucleus is the massive center of the atom. It was discovered in 1911 but it took another 21 years of experimenting to identify what it was made up of.
Protons
Neutrons

11. Scientists thought that there was nothing smaller than the proton in the nucleus of the atom.

12. In 1968 scientists discovered new particles inside the proton
In 1968 scientists discovered new particles inside the proton. They called these particles quarks.

13. There are three quarks in each proton
There are three quarks in each proton. Quarks are held together by other particles called gluons.

14. In the neutrons they found the same thing…..
Quarks and gluons.
So, in summary, the center of the atom contains two different particles called protons and neutrons (which are made of quarks). This center is called the nucleus. Around the nucleus electrons are found.

15. Electrons are extremely small and very light
Electrons are extremely small and very light. It is easy to strip electrons off of atoms and use them for electrical power and in devices like TV sets

16. Science TV
Atom - Electrons

17. Question
Empty Space
Most of an atom consists of ______________ ?

18. Science TV
Atom – Scale of the atom

19. Analogy…….. The Meadowlands

20. So how many protons, neutrons, and
electrons does an atom
exactly have??? ? ? ? ? ? ? ? ?
Welllllll, it all depends on which one of the 115 (or so) atoms it is…. ? ? ? ? ? ?

21. What pattern do you see here???
Look closely…..

22. In an atom there will always be the same number of protons (+) as there are electrons (-).
As a result, most atoms are electrically neutral – the positives cancel out the negatives.
Gold (Au)
Sodium (Na)

23. Electrons are so light they are not figured in on the mass of an atom
Electrons are so light they are not figured in on the mass of an atom. (Kind of like having an ant on your arm when you weigh yourself. The ant really isn’t adding significant weight to you).

24. Although more details of the atom were discovered in the 1900’s a man named John Dalton came up with something called the Atomic Theory in Dalton was the guy that was able to link what was known about atoms to the elements.
Dalton was an English school teacher and scientist .

25. Science TV
Atom - Dalton

26. Here’s what Dalton’s atomic theory said:
Every element is made of atoms - piles of paper clips.
All atoms of any element are the same - all the paper clips in the pile are the same size and color.
Atoms of different elements are different (size, properties) - like different sizes and colors of paper clips.
Atoms of different elements can combine to form compounds - you can link different sizes and colors of paper clips together to make new structures.
In chemical reactions, atoms are not made, destroyed, or changed - no new paper clips appear, no paper clips get lost and no paper clips change from one size/color to another.
In any compound, the numbers and kinds of atoms remain the same - the total number and types of paper clips that you start with are the same as when you finish.