Introduction to Atomic Theory OBJ 1: Compare the different models of an atom. OBJ 2: Explain how atomic theory has changed as scientists have discovered

Introduction to Atomic Theory

OBJ 1: Compare the different models of an atom. OBJ 2: Explain how atomic theory has changed as scientists have discovered new information about the atom.

Homework: Read pages 87-93. Purpose for reading: Take notes on “terms to learn.” Science in the News #9 due 11/6 and #10 due 11/13.

*TURN in Periodic table activity!*ALL SF Experiments are to be done by 11/26

Warm-up: Why is it important to repeat an experiment?

Today is November 6th

To do:

Complete page 83 Section ReviewSugar Cube Lab



Homework: Review pages 87-93.” Science in the News #10 due 11/13.

*ALL SF Experiments are to be done by 11/26

Warm-up: none


To do:Sugar Cube Lab:

1.) Review procedures– Be sure you aren’t missing any info2.) Begin lab 3.) Go on to day 3


OBJ: Same.

Warm-up: none.

To do: See above slides

Homework: Science in the News #10 due 11/13.Study terms.

*ALL SF Experiments are to be done by 11/26.




Homework: Science in the News# 10 due 11/13. Study terms.

*ALL SF Experiments are to be done by 11/26.

To do: See next slide


To do:

1.) 10 minutes to finish Sugar Cube Lab2.) Jigsaw

Activities Today: “A timeline of the Atom”

1.You will be put into groups.2.I will assign you a person to research in the book3.Research that person.4.Write a word, phrase or sentence that the person would likely say about the atom. 5.Describe the tools that person used to make his discovery.6.Make an atom model that the person proposed. 7.We will come back together to make a timeline & present.

To-Do List:

Word or phraseToolAtom Model

Group 1: DaltonGroup#2: RutherfordGroup# 3: Thomson

Group# 4: BohrGroup# 5: Democritus

Groups/ Assignment

Conclusion

How does mixing or stirring, heating and crushing a solute affect how quickly solids dissolve in liquids?



Homework: Review all notes.

* TURN in Science in the News #10* ALL SF Experiments are to be done by 11/26.

To do: See next slides


To do:

1.) Jigsaw2.) Notes

Atoms:*Small*Hard*Made of single material in differ shapes/ sizes*Always moving*Form different materials by joining together

Democritus:

*“uncuttable” particle = atom (“indivisible”)

Dalton: Atomic Theory

1.) All substances: made of atoms“atoms cannot be created or destroyed”2.) Atoms of the SAME element are exactly alike3.) Atoms join with other atoms to form NEW substances

Hmm…

J.J. Thomson:

*Small particles ARE inside atom*Atom CAN be dividedNegative Corpuscles = electrons*Atoms have no overall charge, thus positive charge MUST be present*Plum-pudding model

http://www.chem.uiuc.edu/clcwebsite/cathode.html#

Ernest Rutherford:

Atoms were NOT soft “blobs”*Particles deflected- bounced in various directionsTHUS:*Center of atoms = positive charge (nucleus)*particles that headed toward nucleus were pushed in the opposite direction*New model

Niels Bohr:

*Electrons travel around nucleus in definite paths*Paths are at certain distances from nucleus*Electrons jump

Atomic orbitals are the basic building blocks of the atomic orbital model (alternatively known as the electron cloud or wave mechanics model),

Modern Quantum Theory

Modern Quantum Theory:•Max Planck•Louis de Broglie •Erwin Schrodinger•Wolfgang Pauli •Max Born &Werner Heisenberg•James Chadwick•Murray Gell-Mann•George Zweig•Albert Einstein•Marie Curie•Lise Meitner•Enrico FermiAnd ….

http://atomictimeline.net/index.php

Ruđer Josip Bošković

Who do you think had the biggest impact on today’s present-day atomic theory?

ConclusionTake a QUIZ: http://www.neok12.com/quiz/ATOM0005


OBJ 1- 2: See previous slides. OBJ 3: Compare the charge, location, and relative mass of protons, neutrons, and electrons.OBJ 4: Calculate the number of particles in an atom using the atomic number, mass number, and overall charge.

Homework: {Review pages 84-93 (i.e. skim your notes)} Answer Section Review questions on pages 86, 89 and 93. *TEST on 11/21



* ALL SF Experiments are to be done by 11/26.

An An IntroductiIntroducti

on to on to Atomic Atomic ModelsModels

Atomic Theory?In the following lectures, you will learn about the

Atomic - Molecular Theory of Matter. You will also learn about scientists

and how they have gathered evidence

about atoms.

Please Take Notes in your

Notebook as we proceed!

Atomic - Molecular Theory of Matter

The Atomic - Molecular Theory of Matter states

that all matter is composed of small, fast moving particles called atoms. These atoms can join together to

form molecules.

This theory is really thousands of individual ideas and models that provide evidence for the whole theory.

MatterSince the atom is Since the atom is too small to be too small to be seen even with seen even with

the most the most powerful powerful

microscopes, microscopes, scientists rely scientists rely

upon models to upon models to help us to help us to

understand the understand the atom.atom.

Believe it or not this is a Believe it or not this is a microscope. Even with the microscope. Even with the worldworld’’s best microscopes s best microscopes

we cannot see the we cannot see the structure or behavior of the structure or behavior of the

atom.atom.

Scientific Models Scientists create

models to help them to visualize

complex properties, structures or

behaviors. Since the atom is so

small, scientists must gather

Indirect Evidence to develop their

models.

This is a model of one very This is a model of one very complex molecule made of complex molecule made of

many different kinds of many different kinds of atoms. Each colored ball atoms. Each colored ball represents an atom of a represents an atom of a

different element.different element.

What should a Model look like?

Scientific models may not always

look like the actual object. A

model is an attempt to use

familiar ideas to describe

unfamiliar things in a visual way.This is a painting of a young This is a painting of a young

woman by Pablo Picasso. Does woman by Pablo Picasso. Does it actually look like a young it actually look like a young

woman?woman?

Is this really an Atom?

The model above represents the most

modern version of the atom, but it’s still a model

(Artist drawing)

Many of the models that you Many of the models that you have seen may look like the one have seen may look like the one

below. It shows the parts and below. It shows the parts and structure of the atom. Even structure of the atom. Even

though we do not know what an though we do not know what an atom looks like, scientific atom looks like, scientific models must be based on models must be based on

evidence. evidence.

Indirect EvidenceIndirect Evidence is evidence gathered

without being able to directly observe the object. The Atomic -

Molecular Theory of Matter is based upon a vast amount of indirect

evidence gathered over a long period of time. Just like pieces being added

to a puzzle, each new bit of information gives us a better

understanding of atoms.

How can Indirect Evidence be Gathered?

Pretty much everything we

know about atoms is indirect

evidence. One can't really see

atoms. We do see enough of their effects that we

can, with confidence, describe the

nature of atoms.

It's like putting together a puzzle that's missing some pieces. If you

get enough pieces in the right place you can tell what the picture is even though it still has holes.

Can a Model be Changed?

A model can be changed as new information is

collected. From the early Greek concept

to the modern atomic theory, scientists have built upon and modified existing

models of the atom.

Where did it all begin?

The word “atom” comes from the

Greek word “atomos” which

means indivisible.

The idea that all matter is made up of atoms was first proposed by the

Greek philosopher Democritus in the 5th century B.C.

More HistoryThe concept of atoms as proposed by Democritus

remained relatively unchanged for over

2,000 years. Beginning in the late 18th century new discoveries were

made that led to a better understanding of atoms

and chemistry. Many scientists since that time

have contributed new evidence for the

“Atomic Theory”

Niels Bohr is one of Niels Bohr is one of many scientists that many scientists that

have given us a have given us a better understanding better understanding

of Atoms.of Atoms.

How small is an atom?

Bryson? 3 hundred-millionths of a centimeter

“Weighing” an atom

Since atoms are sooo small, scientists developed a new unit: Atomic mass unit (amu):

1 Proton = 1 amu 1 neutron = 1 amu 1 electron = almost 0 (we don’t consider the

mass of an electron when finding the mass number). It takes more than 1800 electrons to equal 1 amu.

The Nucleus

Small, positively charged center of the atom.

Contains most of the atom’s mass

Inside the Nucleus

Protons: positively charged particles

Neutrons: particles in atom with no charge

What is the charge of the nucleus?

Outside the nucleus

Electrons: negatively charged particles in atoms.

Likely to be found around the nucleus within electron clouds

What makes up P, N & E?

Take a QUIZ:

http://www.neok12.com/quiz/ATOM0001




The Atom

OBJ 1- 4: See previous slides.

Take out: Section Review questions on pages 86, 89 and 93.

Homework: *TEST on 11/21




An Atom is neutral!

Equal number of protons and electrons

The charges of protons and electrons are opposite, but equal in size.

What if they aren’t equal?

Ions

A charged particle If # protons > # electrons . . .

If # protons < # electrons. . .

Elements & Atoms

Each element is made of a different amount of protons, neutrons, and electrons.

For example: Hydrogen= 1 proton, 0 neutron, 1 electron Helium= 2 protons, 2 neutrons, 2 electrons Gold= 79 protons, 118 neutrons, 79

electrons

ATOMIC NUMBER: THE NUMBER OF PROTONS IN THE NUCLEUS OF THE ATOM

ALL ATOMS OF THE SAME ELEMENT HAVE THE SAME AMOUNT OF PROTONS.

So…the amount of P doesn’t have to equal N. . .

Isotopes: atoms that have the same number of protons, but a different number of neutrons.

This means it has a different mass number.

Mass number = Sum of protons + neutrons Boron= 5 Protons + 5 Neutrons = 10 amu Or 5 Protons + 6 Neutrons = 11

amu

Properties of Isotopes

Each element has a limited number of isotopes (meaning, you can’t assign “random” numbers of neutrons)

Can be unstable: meaning, the nucleus can change it’s composition. If it is unstable it’s RADIOACTIVE

Will have the same physical & chemical properties of the stable isotope

To find the # of neutrons Simple subtraction Mass Number – Atomic number (# of

p) Carbon -12 Mass number= 12 Atomic Number= 6 Neutrons= 6

Calculating the Mass of an Element Atomic Mass: weighted average of

the masses of all naturally occurring isotopes of an element

MathBREAK on page 92: To calculate the atomic mass of an element, multiply the mass number of each isotope by its percentage abundance in decimal form. Then add these amounts together to find the atomic mass.

Calculate the Atomic MassWhat is the atomic mass of:• Titanium-46 (8%)• Titanium-47 (7.3%)• Titanium-48 (73.8%)• Titanium-49 (5.5%)• Titanium-50 (5.4%)

“Made to Order” No new objectives. Homework: Test on 11/21. Handout

and Lab (finish whatever you didn’t finish in class today!)

Warm-up: Copper- 63 occurs in nature 69% of the time. Copper- 65 occurs in nature 31% of the time. Calculate the Atomic Mass.

How do I calculate this?!



Concept Map

Higgs Boson Explained video: http://player.vimeo.com/video/

41038445?portrait=0&amp

Example

Calculate

Boron Boron-10 occurs 20% Boron- 11 occurs 80%

Forces in an atom

Gravity: (acts between all objects) It affects an atom, but very small affect.

Electromagnetic Force: Same charges repel, opposite charges attract. This is what holds electrons around the nucleus.

Strong Force: keeps the nucleus together because protons would repel each other. Stronger than E.M. Force.

Weak Force: in radioactive atoms. . .a neutron can change into a proton.

Draw a concept map

Proton Atomic mass unit Neutron Atomic number Isotopes Mass number Atomic mass

Atom Builder Activity

http://www.nclark.net/Atom_Builder.pdf

“Made to Order” No new objectives. Homework: Study- Test on 11/21

To Do: Questions about SF Check last night’s HWNotes from yesterday



“Made to Order” No new objectives. Homework: TEST on 11/21.

To Do: QuestionsLesson Wrap-up: Chapter Review



TEST right NOW!

Homework:

Today is November 21st


REVIEW of SMALL PARTICLE THEORY

Homework: none- if you do your work!-BOTH labs are due by the end of class on 11/25!

To do: What does the small particle theory say… again?

For today and tomorrow we will…

• ALL SF Experiments are to be done by 11/26.• FULL SF papers (DRAFT ONLY) are due 12/3

The Particle Theory of Matter:1. Matter is made up of tiny particles (Atoms &

Molecules)2. Particles of Matter are in constant motion.

3. Particles of Matter are held together by very strong elastic forces

4. There are empty spaces between the particles of matter that are very large compared to the particles

themselves.5. Each substance has unique particles that are different

from the particles of other substances6. Temperature affects the speed of the particles. The

higher the temperature, the faster the speed of the particles.

The particle theory of matter explains the following scientific phenomena:

• Pure substance are homogeneous (one phase - one unique kind of particle)

• Physical Changes - Melting, Evaporation, Sublimation, Dissolving.....

• Characteristic Physical Properties - Density, Viscosity, Electrical & Thermal Conductivity

Next up: LABS*Molecular Motion and Spacing

* Space between particles of liquid

Documents

Introduction to Atomic Theory OBJ 1: Compare the different models of an atom. OBJ 2: Explain how atomic theory has changed as scientists have discovered