1. 4.2 The Structure of an Atom NEW - Opener #1 TUES 10-12-10 (8th grade standard) - Hint: see ch. 4.2 & 4.1 if needed... 1. What is an atom? 2. What are 3 subparts that make up an atom? 3. What are the charges of these subparticles of the atom? Identify each. 4. Where are the subparticles located within the atom? CW: Notes 4.2 PART 1 CW: INTRO. Atom Project CW: Scientist Contribution Poster Element quiz: Friday, Oct. 22nd.

2. 4.2 The Structure of an Atom This 45-foot-tall steel sculpture is made of 10 tons of steel. If a proton had the same mass as the sculpture, then an electron would have a mass of about 5 kilograms.

3. 4.2 The Structure of an Atom What are three subatomic particles? Properties of Subatomic Particles Protons, electrons, and neutrons are subatomic particles.

4. 4.2 The Structure of an Atom Protons Based on experiments with elements other than gold, Rutherford concluded that the nucleus contained particles of positive charge. A proton is a positively charged subatomic particle that is found in the nucleus of an atom. Each proton is assigned a charge of 1+. Each nucleus must contain at least one proton. Properties of Subatomic Particles

5. 4.2 The Structure of an Atom Electrons The negative charges that were detected by Thomson were later named electrons. An electron is a negatively charged subatomic particle that is found in the space outside the nucleus. Each electron has a charge of 1 −. The mass of an electron is 1/1836 the mass of the proton. This is the reason that the atomic mass is basically the mass of the protons + mass of neutrons... Properties of Subatomic Particles Analogy: 1000 + 1000 + 0.001... 2000.0001 The 0.001 would insignificant compared to the other 2 numbers...

6. 4.2 The Structure of an Atom Neutrons In 1932, the English physicist James Chadwick carried out an experiment to show that neutrons exist. Chadwick concluded that the particles he produced were neutral because a charged object did not deflect their paths. A neutron is a neutral subatomic particle that is found in the nucleus of an atom. It has a mass almost exactly equal to that of a proton. Properties of Subatomic Particles

7. 4.2 The Structure of an Atom What properties can be used to compare protons, electrons, and neutrons? Comparing Subatomic Particles Protons, electrons, and neutrons can be distinguished by mass, charge, and location in an atom.

8. 4.2 The Structure of an Atom Everything scientists know about subatomic particles is based on how the particles behave in experiments. Scientists still do not have an instrument that can show the inside of an atom. Comparing Subatomic Particles

9. 4.2 The Structure of an Atom Here are some similarities and differences between protons, electrons, and neutrons. Protons and neutrons have almost the same mass. About 2000 electrons equal the mass of one proton. An electron has a charge that is equal in size to, but the opposite of, the charge of a proton. Neutrons have no charge. Protons and neutrons are found in the nucleus. Electrons are found in the space outside the nucleus. Comparing Subatomic Particles

10. 4.2 The Structure of an Atom Continue after about 6:44 minutes have passed...

11. 4.2 The Structure of an Atom click here for parts of the atom to show what your model will look like... http://my.hrw.com/sh/hk6_0030390966/student/ch04/sec01/vc01/hk604_01_v01fs.h tm my.hrw.com (PS section 4.1)

12. 4.1 Studying Atoms Partner Poster Project of Scientists of Atomic Theory... Create a poster of one of the following scientist(s)... illustrating what they helped contribute to the atomic theory... Aristotle & Democritus Dalton Thomson Rutherford OTHER with approval... Faraday, Mendeleev, Bohr, Millikan, Schrodinger, Chadwick, Heisenberg, Einstein & de Broglie There are colored pencils and markers available in blue tub in back by sink. All drawings should take up most of a regular size copy sheet of paper and be in color. Words may also be used to describe contribution.

13. 4.2 The Structure of an Atom WORK ON SCIENTIST POSTER PROJECT... INTRODUCTION TO THE ADOPT AN ELEMENT PROJECT...