Upload File

atomic structure the idea of the atom early models greek philosophers – 450 b.c. what is the...

  • Home
  • Documents
  • Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An
47
Atomic Structure The Idea of the Atom

Upload: alexandrina-barber

Post on 27-Dec-2015

214 views

Category:

Documents


0 download

Report

Tags:

TRANSCRIPT

Page 1: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Atomic Structure

The Idea of the Atom

Page 2: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Early Models Greek philosophers – 450 B.C. what is the

smallest particle? Democritus - Particles are atomos An atom is the smallest particle of an

element that retains the chemical identity of that element.

Page 3: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Aristotle Wins Greek society - slave based Beneath them to work with hands – no

experiments Settled disagreements by arguments Aristotle more famous than Democritus

Aristotle wins Didn’t believe or look into atoms until…

Page 4: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Late 1700s Chemists believed elements:

couldn’t be broken down by ordinary means Combine to form compounds

Advancements in balances better experiments

Page 5: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Laws Discovered Law of Conservation of mass: mass is neither

created nor destroyed during chemical or physical changes

Then discovered no matter where or how a compound is made it is made of fixed proportions of elements Law of Definite Proportions

Ex: Sodium Chloride, table salt, always has 39.34% Na and 60.66% Cl by mass

Page 6: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Laws Discovered Elements combine to form more than one

compound Ex: carbon monoxide, CO, and carbon dioxide CO2

Law of Multiple Proportions

Page 7: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

John Dalton 1808 –DALTON’S ATOMIC THEORY

1. All matter is composed of small particles called atoms.

2. *All atoms of a given element are identical, but they differ from those of any other element.

Page 8: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Dalton’s Atomic Theory3. *Atoms cannot be subdivided, created, or

destroyed

4. Atoms of different elements combine in whole-# ratios to form compounds

5. In a chemical reaction, atoms are combined, separated, or rearranged.

Page 9: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

1800s – The atom IS divisible Atom has two regions:

Nucleus: center of atom Protons: (+) charged Neutrons: no charge

Electron cloud: region around nucleus containing electrons, (-) charged

Subatomic particles: p+, no, and e-

Page 10: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Voltage source

+-

Moving electrical current (Cathode Ray) through glass tube with inert gas (Noble Gas)

J.J. Thomson’s ExperimentCathode - Ray Tube

Page 11: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Voltage source

J.J. Thomson’s ExperimentJ.J. Thomson’s Experiment

• By adding magnets, found the moving (-) particles By adding magnets, found the moving (-) particles

+

-

Page 12: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Thomson’s Model Same properties no

matter what element used

All atoms had ELECTRONS!!

Thomson’s Model Plum pudding: bunch of positive stuff, with the electrons able to be removed.

Page 13: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Ernest Rutherford - 1911 Atoms have e- = (-) charge Atoms are neutral need (+) to balance Must be other particles to account for mass

of atom… Rutherford used alpha particles to test.

Alpha particle: (+) charge, (2 p+ and 2 no) Experiment: beam of high speed alpha

particles into thin gold foil

Page 14: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Mr. Green. Mr. Green’s Homepage. 10 Sept. 2003. http://www.tvgreen.com/index.htm. 21 Aug. 2004

Lead block

Uranium

Gold Foil

Florescent Screen

Page 15: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Mr. Green. Mr. Green’s Homepage. 10 Sept. 2003. http://www.tvgreen.com/index.htm. 21 Aug. 2004

His prediction….

Page 16: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Mr. Green. Mr. Green’s Homepage. 10 Sept. 2003. http://www.tvgreen.com/index.htm. 21 Aug. 2004

What he expected

Page 17: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Mr. Green. Mr. Green’s Homepage. 10 Sept. 2003. http://www.tvgreen.com/index.htm. 21 Aug. 2004

What he happened

Page 18: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Results… Most particles passed through 1 in 8000 bounced back Some particles completely reversed path!!!

Page 19: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Mr. Green. Mr. Green’s Homepage. 10 Sept. 2003. http://www.tvgreen.com/index.htm. 21 Aug. 2004

Plum-pudding is WRONG!

+

Atom is mostly empty Small dense,

positive pieceat center, nucleus

Alpha particlesare deflected by nucleus if they get close.

Page 20: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Mr. Green. Mr. Green’s Homepage. 10 Sept. 2003. http://www.tvgreen.com/index.htm. 21 Aug. 2004

+

Page 21: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Electron Cloud Model Current model of atom Nucleus surrounded by negative cloud

“electron cloud”

Page 22: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Size of Atom Atom = size of football stadium Nucleus = smaller than a dime in center Electron = each one smaller than

Roosevelt’s eye on the dime Atom is mostly empty space!

Page 23: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Composition of Atom Proton has (+) charge equal in magnitude to (-)

charge of electron Atoms neutral # p+ = # e-

p+ and no about same mass e- = 1836 times smaller than p+

Nucleus has majority of mass Nuclear Forces: short-range forces that hold

nucleus together p+-p+, p+-no, no-no

Page 24: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Counting Atoms Atomic Number (Z): number of p+ of

each atom of the element

Identifies Elements!!

Page 25: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Atomic Number What is the atomic number for… Hg What is the element with … 20 p+

Neutral atoms # p+ = # e-

In neutral atoms, atomic number = # e-

Page 26: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Isotopes Def: atoms of same element with different

# of no (different masses) 3 H isotopes:

Protium: 1 p+ 99.9885% Deuterium: 1 p+ 1 no 0.0115% Tritium: 1 p+ 2 no

Page 27: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Mass Number Use mass number to determine isotopes Mass #: # of p+ and n0

Atom with 17 p+ and 20 no has mass # of… Chlorine-37 – Hyphen Notation

Page 28: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Writing Isotopes Nuclear symbol:

Cl37

17Elemental symbol

Mass number

Atomic number

Page 29: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Finding # of Neutrons # of neutrons = mass # - atomic # How many p+, no and e- are in… Selenium – 79

27Al

Oxygen - 18

13

Page 30: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Isotopes Write the complete chemical/nuclear

symbol for the isotope with 21 protons, 24 neutrons, and 21 electrons.

Page 31: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Relative Mass of Atom Mass of Oxygen-16 = 2.656 x 10-23 g Use relative atomic masses Pick standard other masses are

expressed in relation to standard Standard: Carbon –12 atom

Page 32: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Carbon - 12 Has mass of 12 atomic mass units (amu) 1 amu: is exactly 1/12 the mass of a

carbon-12 atom Carbon-12: how many p+ and no? 1 p+ 1 amu (1.007276 amu) 1 no 1 amu (1.008665 amu) 1 e- 0 amu (0.005486 amu)

Page 33: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Carbon - 12 What element is 4 x mass of Carbon –12? What element is 1/3 mass of Carbon –12?

Page 34: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Average Atomic Masses Most elements are mixture of isotopes Mass of element is average mass of

isotopes We need the % of each isotope Average Atomic Mass: weighted average

of the atomic masses of the naturally occurring isotopes of an element.

Page 35: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Weighted Average Box with 100 marbles of 2 sizes:

25% have mass of 2.00g 75% have mass of 3.00g

What is the average mass of a marble? 2.75g (sig figs!!)

Page 36: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Average Atomic Mass Or (atomic weight) found on periodic table

(ROUND TO 2 DECIMAL PLACES!!) Average Atomic Mass =

(% Iso. #1)(Mass Iso.#1) + (%Iso.#2)(Mass Iso.#2) + …

100

Page 37: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Average Atomic Mass Find the atomic mass of Li if… 7.5% is Lithium – 6 = 6.015 amu 92.5% is Lithium – 7 = 7.016 amu

Page 38: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Example – AAM = 16.00 amuIsotope Fractional Abundance

Oxygen – 16 (15.99 amu) 99.757%

Oxygen – 17 (17.00 amu) .038%

Oxygen – x .235%

Page 39: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

The Mole

Page 40: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Quantities 1 dozen =

12 1 gross =

144 1 ream of paper =

500 In chemistry: 1 mole = 6.022 x 1023

Page 41: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

The Mole SI unit for amount of substance (mol) Def: the number of particles in exactly 12

g of carbon – 12. 12 g of carbon –12 has 6.022 x 1023 atoms Avogadro’s #, after Amadeo Avogadro The number is HUGE!!

Page 42: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Molar Mass Def: mass of 1 mole of a pure substance 1 mole Carbon –12 = 12 g 1 atom Carbon – 12 = 12 amu Mass of 1 mole of He atoms? 4.00g/mol Same as atomic mass from periodic table,

different units

Page 43: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Molar MassSo: 4.00g He, 6.94 g Li and 200.59 g Hg all

have 6.022 x 1023 atoms = 1 mole!!! Molar mass (g/mol) conversion factor!!

Page 44: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Gram/Mole Conversions

Mass, in g, of 3.6 mol of C? 43g

How many moles are in 23.5 g S? 0.733 mol

p. 85 problems

Page 45: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Conversions with Avogadro’s # Diatomic Molecules: elements that exist

as 2-atom molecules in natural state 7 diatomic molecules H2, O2, N2, F2, Cl2, Br2, I2

Remember!!! HONClBrIF

Page 46: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Conversions with Avogadro’s # How many moles of oxygen are in

2.00x1022 molecules of oxygen? How many atoms of sodium are in 3.80

mol of sodium?

Page 47: Atomic Structure The Idea of the Atom Early Models Greek philosophers – 450 B.C. what is the smallest particle? Democritus - Particles are atomos An

Conversions with Avogadro’s # How many molecules of hydrogen are in

0.020 g of hydrogen? Mass of 5.0x109 atoms of neon? p.86 problems


1.3 Atomic Theory Greek philosophers believed that matter was made of atomos that were the smallest pieces of matter. Aristotle believed matter was

Democritus: Believed all matter consisted of extremely small particles that could not be divided. Called these particles “Atomos”- Greek word meaning

Chapter 2 (Part I) Atoms, Molecules, and Ions History n Greeks n Democritus and Leucippus - atomos n Aristotle- elements n Alchemy n 1660 - Robert Boyle-

Basic Chemistry Atoms, Elements & Molecules. Atoms Around Us “To understand the very large, we must understand the very small” Democritus Atoms Atomos

HISTORY OF STRUCTURE OF THE ATOM Early models of the atom Century 5 th BC, Democritus used the word “atomos.” He said that the differences between substances

Chapter 2 Atoms, Molecules, and Ions History n Greeks n Democritus and Leucippus - atomos n Aristotle- elements. n Alchemy n 1660 - Robert Boyle- experimental

1. 2 Early Thoughts 3 Democritus (about 470-370 B.C.) thought that all forms of matter were made of tiny particles called “atoms” from the Greek “atomos”

Chapter 4 Atomic Structure p. 101. Section 4.1 Defining the Atom Greek philosopher Democritus Greek philosopher Democritus suggested atoms (Greek “atomos”)

Physical Science CHEMICAL BONDS. Atomic Models in History Democritus, Greek philosopher, around 400 BC used the term “atomos” which means “indivisible-unbreakable”

Atoms and the Periodic Table The Atom Ch. 4. Democritus (400 BC) Greek philosopher. All things are composed of tiny, indivisible particles: called: Atomos

Pre-Socratic Philosophers. Reality is One Thales Anaximander Anaximenes Pythagoras Heraclitus Parmenides Zeno Reality is Many Empedocles Anaxagoras Democritus

Atomic Theory-Democritus Greek philosopher, 400 BC Greek philosopher, 400 BC Named the smallest piece of matter “atomos,” meaning “not to be cut.” Named

Atoms, Molecules, and Ions Chapter 2. Democritus 460 BC 460 BC First to propose atomic nature of matter First to propose atomic nature of matter “atomos”

Electrons in Atoms: LIGHT & QUANTIZED ENERGY. Review and Background 400 B.C.E. – Democritus: proposed that all matter is composed of “atomos”

History of Atomic Structure Chemistry. Democritus (460-370 BC) Goal of Greek philosophers was to explain the natural world Believed that all materials

1 Chapter 5 Atoms, Molecules, and Ions 2 History n Greeks n Democritus and Leucippus - atomos n Aristotle- 4 elements. n Alchemy-experimentation n 1660

Unit 2: Atomic Theory and Structure. (c. 400 B.C.) Democritus proposed that “atomos” are indivisible. Atom: smallest particle of matter that retains its

Chapter 4 The Structure of the Atom. Chapter 4 Democritus: Greek philosopher coined the word “atom”. Greek word comes from “atomos” meaning indivisible

Atomic Theory. Democritus – 460 – 370 BC Matter consisted of tiny particles “atomos” Ideas were wrong

History of the Atom. Democritus (400 BC) Proposed that matter was composed of tiny, invisible particles. Gr. atomos

Development of the Atomic Theory. Democritus 460 BC - Greek philosopher proposes the existence of the atom ; calls it Atomos meaning indivisible. His

The History of Atomic Structure. Democritus Named the atom from the Greek word “atomos” meaning indivisible. Wrote that atoms were the smallest unit

Religion, science and philosophy. New AtheistsAgnosticsChristian theists Democritus Epicurus Lucretius Plato, Aristotle Stoic, sceptic Philosophers Egyptians

Atomic Theory Past and Present. A. Democritus (400 BCE) Matter is made up of particles called “atomos” or atoms

The History of the Atom……. Democritus was the first to theorize that all matter was composed of atoms! The name atom comes from his Greek word, “atomos”,

CHAPTER 2-1. ATOMS Atom – is the basic unit of matter – Ex. Democritus – breaking a piece of chalk, when is it not chalk anymore? Until atomos “unable

1.cdn.edl.io · Web viewBasic Overview of Atomic Theory Atomic Theory – History Democritus – “ Atomos ” – indivisible particles Lavoisier – Law of Conservation of Mass/Matter

The Atom. The Building Block of Matter 400 BC Democritus (Greek Philosopher) Atomos = “indivisible” …like a brick is used to build a building; an

Chapter 2 Atoms, Molecules, and Ions History n Greek philosophers n Democritus and Leucippus - atomos n Aristotle- 4 elements: Earth, Air, Fire, and

Democritus and the Natural Philosophers Greek geeks and what they thought

Chapter 2 Atoms, Molecules, and Ions History n Greeks n Democritus and Leucippus - atomos n Aristotle- elements n Alchemy n 1660 - Robert Boyle- experimental

Chapter 2 Atoms, Molecules, and Ions. History Greeks Greeks Democritus and Leucippus - atomos Democritus and Leucippus - atomos Aristotle- elements Aristotle-

Mullis1 Democritus (460-370 B.C.) Democritus was one of a few Greek philosophers who believed that all matter in the world was made of of indivisible parts

HISTORY OF THE ATOM. DEMOCRITUS – 400B.C. A.He believed matter was made up of empty space and tiny particles he called “atomos” B.Said different things

ATOMS, MOLECULES AND IONShaydukscience.weebly.com/uploads/2/0/9/7/20974360/... · Democritus theorized that matter was built of ‘tiny indivisible particles’called atomos but this