4.1 studying atoms monday, october 11, 2010 3rd/4th/5th/7th periods - have out notes and 15 openers...

4.1 Studying Atoms

Monday, October 11, 2010

3rd/4th/5th/7th periods - Have out notes and 15 openers for me to pick up.

3rd/4th - You should have pencil & 2 sheets of paper unless you already have done your take home essay question. You will have calculator & reference sheet for testing.#1-39 will be entered into the computer once you have finished those parts.

HW: Take Home Essay questions are due tomorrow... but may be turned in today. 6th period - Computer Activity Games - 6th period test tomorrow ch. 3

5th/7th period - Finish test part 2. Turn in take home essay questions.Introduction to new unit. Notes 4.1 started....

ALL CLASSES: Turn in your computer activities GAME lab IN BOX.

4.1 Studying Atoms

Tuesday, October 12, 2010 - 6th period only...

6th period - Have out notes ch. 3 for me to pick up.

- You should have pencil & 2 sheets of paper unless you already have done your take home essay question. You will have calculator & reference sheet for testing.#1-39 will be entered into the computer once you have finished those parts.

HW: Take Home Essay questions are due tomorrow... but may be turned in today.


4.1 Studying Atoms

Tuesday, October 12, 2010 -3rd/4th periods only...

3rd/4th - Finish Questions #40-54. Turn in with Take Home essay question. Introduction to new unit. Notes 4.1 started....


Introduction to Project...

Element Quiz - Friday, October 22nd over 53 element symbols/names...

4.1 Studying Atoms

Studying the structure of atoms is a little like studying wind. Because you cannot see air, you must use indirect evidence to tell the direction of the wind. Atoms pose a similar problem because they are extremely small. Even with a microscope, scientists cannot see the structure of an atom.

I set up to automatically play short audio clip - song about atom/matter while you read first 3 screens.

4.1 Studying Atoms

If you cut a piece of aluminum foil in half, you have two smaller pieces of the same shiny, flexible substance. You could cut the pieces again and again. Can you keep dividing the aluminum into smaller pieces? Greek philosophers debated a similar question about 2500 years ago.

Ancient Greek Models of Atoms

4.1 Studying Atoms

The philosopher Democritus believed that all matter consisted of extremely small particles that could not be divided. He called these particles atoms from the Greek word atomos, which means “uncut” or “indivisible.”


4.1 Studying Atoms

Aristotle thought that all substances were made of only four elements—earth, air, fire, and water. He did not think there was a limit to the division of matter. For many centuries, most people accepted Aristotle’s views on the structure of matter. By the 1800s, scientists had enough experimental data to support an atomic model.


4.1 Studying Atoms

What was Dalton’s theory of the structure of matter?

Dalton’s Atomic Theory around 1803

Dalton proposed the theory that all matter is made up of individual particles called atoms, which cannot be divided.

4.1 Studying Atoms

Evidence for AtomsJohn Dalton studied the behavior of gases in air. Based on the way gases exert pressure, Dalton correctly concluded that a gas consists of individual particles.

Dalton measured masses of elements that combine when compounds form. The ratio of the masses of the elements in each compound was always the same. In other words, compounds have a fixed composition.

Dalton’s Atomic Theory

4.1 Studying Atoms

When magnesium burns, it combines with oxygen. In magnesium oxide, the ratio of the mass of magnesium to the mass of oxygen is always about 3 : 2. Magnesium dioxide has a fixed composition.


4.1 Studying Atoms

Dalton’s Theory• All elements are composed of atoms.• All atoms of the same element have the same mass,

and atoms of different elements have different masses.

• Compounds contain atoms of more than one element.

• In a particular compound, atoms of different elements always combine in the same way.

• Example: there is always 1 C with 2 O’s in the compound carbon dioxide, CO2.


4.1 Studying Atoms

Dalton made these wooden spheres as a model to represent the atoms of different elements. A tiny, solid sphere with a different mass represents each type of atom. Dalton was the first to use scientific evidence to explain the model.


4.1 Studying Atoms

A theory must explain the data from many experiments. Because Dalton’s atomic theory met that goal, the theory became widely accepted.

Over time, scientists found that not all of Dalton’s ideas about atoms were completely correct. They revised the theory to take into account new discoveries.


4.1 Studying Atoms

Thomson experimented with the cathode ray tube.

Thomson’s Model of the Atom - about 1897

Thomson’s experiments provided the first evidence that atoms are made of even smaller particles. note to me:

QUICK LAB PG. 102 WITH TRANSPARENT TAPE BEFORE CONTINUING WITH NOTES.

scotch tape and scissors needed at each table...

4.1 Studying Atoms

When some materials are rubbed, they gain the ability to attract or repel other materials. Such materials are said to have either a positive or a negative electric charge.

• Objects with like charges repel, or push apart. • Objects with opposite charges attract, or pull

together.

Thomson’s Model of the Atom

4.1 Studying Atoms

Thomson’s ExperimentsIn his experiments, Joseph John Thomson used a sealed tube containing a very small amount of gas.

Thomson’s Model of the Atom - Cathode Ray Tube

Sealed tube filled with gas at low pressure

Glowing beam

Metal disk Source of electric current

Metal disk


4.1 Studying Atoms

Thomson’s ExperimentsIn his experiments, Joseph John Thomson used a sealed tube containing a very small amount of gas.


Sealed tube filled with gas at low pressure

Glowing beam


Metal disk


Positive plate

Negative plate

4.1 Studying Atoms

When the current was turned on, the disks became charged, and a glowing beam appeared in the tube.

• Thomson hypothesized that the beam was a stream of charged particles that interacted with the air in the tube and caused the air to glow.

• Thomson observed that the beam was repelled by the negatively charged plate and attracted by the positively charged plate.


4.1 Studying Atoms

Evidence for Subatomic ParticlesThomson concluded that the particles in the beam had a negative charge because they were attracted to the positive plate. He hypothesized that the particles came from inside atoms because

• no matter what metal Thomson used for the disk, the particles produced were identical.

• the particles had about 1/2000 the mass of a hydrogen atom, the lightest atom.


Cathode tube: http://www.youtube.com/watch?v=7YHwMWcxeX8 with magnet...

QuickTime™ and a decompressor

are needed to see this picture.

http://www.youtube.com/watch?v=7YHwMWcxeX8

4.1 Studying Atoms

Thomson’s ModelThomson revised Dalton’s model to account for these subatomic particles.

• The atom has neither a positive nor a negative charge, but there must always be some positive charge in the atom.

• The atom is filled with a positively charged mass of matter that has negative charges evenly scattered throughout it.


4.1 Studying Atoms

Thomson’s model is called the “plum pudding” model. Today, it might be called the “chocolate chip ice cream” model.

The chips represent negatively charged particles, which are spread evenly through a mass of positively charged matter—the vanilla ice cream. Thus, the pudding has a positive charge and the plums represent the negative charge spread evenly throughout.


4.1 Studying Atoms

What contributions did Rutherford make to the development of atomic theory?

Rutherford’s Atomic Theory

According to Rutherford’s model, all of an atom’s positive charge is concentrated in its nucleus.Rutherford discovered that uranium emits fast-moving particles that have a positive charge, called alpha particles.

4.1 Studying Atoms

Ernest Rutherford Experiment in the words from a couple of high school students...

http://www.youtube.com/watch?v=YnfT7jODBYk

http://www.youtube.com/watch?v=YnfT7jODBYk

4.1 Studying Atoms

Formal explanation video

http://www.youtube.com/watch?v=5pZj0u_XMbc&feature=related

http://www.youtube.com/watch?v=5pZj0u_XMbc&feature=related

4.1 Studying Atoms

Rutherford’s HypothesisErnest Rutherford designed an experiment to find out what happens to alpha particles when they pass through a thin sheet of gold.

• Based on Thomson’s model, Rutherford hypothesized that the mass and charge at any location in the gold would be too small to change the path of an alpha particle.

• He predicted that most particles would travel in a straight path from their source to a screen that lit up when struck.


4.1 Studying Atoms

The Gold Foil Experiment


Beam of alpha particles

Source of alpha particles

Slit

Deflected particle

Undeflected particle

Screen

Gold atoms

Alpha particles

Alpha particles

Nucleus

4.1 Studying Atoms

Discovery of the NucleusThe alpha particles whose paths were deflected must have come close to another charged object. The closer they came, the greater the deflection.

However, many alpha particles passed through the gold without being deflected. These particles did not pass close to a charged object.


4.1 Studying Atoms

Thomson’s model did not explain all of the evidence from Rutherford's experiment. Rutherford proposed a new model.

Rutherford concluded that the positive charge of an atom is not evenly spread throughout the atom.


QuickTime™ and a decompressor

are needed to see this picture.

The nucleus of the atom is a dense, positively charged mass located in the center of the atom. The alpha particles that were deflected came very close to a nucleus.

Positive charge is concentrated in a very small, dense central area.

4.1 Studying Atoms

The Houston Astrodome occupies more than nine acres and seats 60,000 people. If the stadium were a model for an atom, a marble could represent its nucleus. The total volume of an atom is about a trillion (1012) times the volume of its nucleus.


4.1 Studying Atoms

Read the following questions and THEN decide which scientist you and a partner will select to illustrate the contributions the scientist made toward the development of atomic theory...

4.1 Studying Atoms

Assessment Questions

1. Dalton’s theory did not include which of the following points? a. All elements are composed of atoms.

b. Most of an atom’s mass is in its nucleus.

c. Compounds contain atoms of more than one element.

d. In a specific compound, atoms of different elements always combine in the same way.

4.1 Studying Atoms


1. Dalton’s theory did not include which of the following points? a. All elements are composed of atoms.

b. Most of an atom’s mass is in its nucleus.

c. Compounds contain atoms of more than one element.

d. In a specific compound, atoms of different elements always combine in the same way.

ANS: B

4.1 Studying Atoms


2. J. J. Thomson’s experiments provided the first evidence of a. atoms.b. a nucleus.c. subatomic particles.d. elements.

4.1 Studying Atoms


2. J. J. Thomson’s experiments provided the first evidence of a. atoms.b. a nucleus.c. subatomic particles.d. elements.

ANS: C

4.1 Studying Atoms


1. #3. The concept of an atom as a small particle of matter that cannot be divided was proposed by the ancient Greek philosopher, Democritus.

TrueFalse

3

4.1 Studying Atoms


1. #3. The concept of an atom as a small particle of matter that cannot be divided was proposed by the ancient Greek philosopher, Democritus.

TrueFalse

ANS: T

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.

4.1 Studying Atoms

WEDNESDAY - APRIL 7, 2010Pick up computer and log-in... (V2 and V5 should be fixed...)1. Have out your notes ch. 2 & 3 along with answer to ch. 3 problems on back of notes with all work shown to turn in. 2. Have out your study guide answers to turn in.3. Turn in endothermic, exothermic, oobleck and slime lab question/answers. (Some have turned these in already but said to hold with openers.)We will turn in the 15 openers tomorrow (not today please...)

TURN IN ALL ITEMS TOGETHER IN BOX... (They do not have to be stapled but should all have your name on them.)

BRING SUPPLIES FOR DRY ICE - ICE CREAM - WE CAN’T DO WITH OUT SOME MORE SUPPLIES... I NEED THESE BY FRIDAY TO SEE IF WE CAN DO.

Element names and symbols test will be on MONDAY!

SAT 10 TESTING FRIDAY - ANNOUNCEMENT FOR WHERE YOU GO - SEE LIST.SIGN UP FOR YOUR ELEMENT TODAY WHILE TESTING...ESSAYS WILL NOT BE DONE ON COMPUTER - DO ON PAPER.

4.1 Studying Atoms

Opener #15 - Tuesday - April 6, 2010 - Pick up remote control...You do NOT have to write in complete sentences today only... but do explain or show work where applicable...

Complete the questions Sect. 3.3 pg. 91 #1-8.

Have out ch. 3 questions (back of ch. 3 notes). We will go over answers. If you did not show work, you will not get points but will turn in tomorrow along with notes ch. 2 and notes ch. 3 for grade.

Be sure chapter 3 questions are turned in the BOX. If they are not turned in today, they are considered late and will lose points.

We will turn in openers on Thursday just to keep my sanity along with the quick lab with endothermic, exothermic, oobleck and slime lab if you didn’t already turn in...

3-D atom due next Wednesday... TEST tomorrow ch.2-3 -- QUIZ Friday (may be moved to Monday...)

Bring supplies for dry ice - ice cream... This may have to be changed to Monday if we are TESTING on Friday with CAPS groups... (?)

4.1 Studying Atoms

Opener #14 - Monday - April 5, 2010You do NOT have to write in complete sentences but do show work for math problems.

1. Complete Section 3.2 pg. 81 #1-10 as opener #14.

CW: Vocabulary Match Game reinforcement Activity...3-D project introduction... with minor change in requirement... due Wed., April 14th...CW: Notes 4.1

CW: Partner Poster Project with Scientists of Atomic Theory...due Thursday in class...

**Turn in ch. 3 assessment questions pg. 94-95-96 IN BOX before leaving today.Be sure you have completed study guide questions by tomorrow if not done...TEST on Wednesday over ch. 2-3...Test on element symbols and names... You will be given name or symbol and have to write the other... spelling does count... computer links are online at podcast page...

HW: Ch.2-3 Problems due tomorrow (see handout on notes ch. 2 and new handout...)

4.1 studying atoms monday, october 11, 2010 3rd/4th/5th/7th periods - have out notes and 15 openers...

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