A.1 - In which you will learn about: Democritus Lavoisier Dalton Thomson Unit 3: Quantum Mechanics Section A: History of Atomic Theory.

Slides:

Advertisements

Similar presentations

Atomic Theory Timeline

Advertisements

Chapter 4 Atomic Structure

Atomic Theories.

ATOMIC STRUCTURE AND HISTORY

Atomic Structure. What is an Atom? The smallest part of an element.

Atoms and the Periodic Table Part I: Historical Background.

Development of Atomic Theory

Grade 9 Science Chemistry Unit: The Study of Matter.

Democritus: The Atom (around 400 BCE)

 You cannot see them, yet they make up everything…

Atomic Theory and the Atom

History of the Atomic Theory

History of Atomic Theory

History of the Atom; Modern Atomic Theory, Subatomic Particles

Atomic Structure History of Atomic Theory. Democritus ( BC) Was the first person to come up with the idea of atom Believed that all matter was.

Early Theories & Subatomic Particles ( )

Atomic Theory PS 9.26 PS 9.27 What is the nature of matter? The ancient Greeks pondered that question. Empedocles in 460 B.C.suggested that all matter.

Development of our understanding of the atom. Early Models Democritus was first to suggest atom in 4 th century B.C. Believed matter was made of tiny.

History of Atomic Structure

Atom Models From Democritus to Bohr’s.

Unit: Atomic Structure

Atomic Theory Chapter 3 Sections 1 &2 9/18/14.

The Development of the Atomic Theory

SCH4C UNIT 1: Matter and qualitative Analysis Atomic Theory

Atomic Structure History and Theories. The Greeks 4 th century B.C. Democritus “Atomists” school of thought Matter is composed of tiny indivisible particles.

History of Chemistry and Atomic Structure Unit 3.

The History of the Atom…. went against, Aristotle, who believed that matter was composed of four qualities: earth, fire, air and water all matter is composed.

Developing a Model of the Atom The History of Atomic Theory.

Atomic Structure. Way Early Theories Democritus ( BC) –First person to propose that matter is not infinitely divisible –Atomos –Matter is empty.

A History of Atomic Theory & Basic Atomic Structure Chapter 3: The Atom Big Idea: Physical, chemical and nuclear changes are explained using the location.

Part I. Leucippus and Democritus (460 to 370 BC) – believed that all matter was made up of tiny particles called atoms. Aristotle (384 to 322 BC) – believed.

Courtesy: B.C. – Matter was composed of four fundamental substances: fire, earth, water, and air. Greeks considered whether matter.

Ch.4 Atomic Structure How do we know atoms exist? Picture, in your mind, what you think an atom looks like.

The Story of the Atom History and Other Early Stories.

The Changing Models of the Atom

Early Ideas about Matter. atom u The smallest piece of the element with all the chemical properties of the element u an old and new idea.

What is an _________? The smallest particle of an ________ that is still an ________ _________ are the building blocks of all ___________.

Atomic Theory. What is an Atom? An ATOM is the smallest part of an element that has all of the element’s properties. Atoms of different elements are different.

Atomic Model History.

History of the Atom. Aristotle (400 BC) 4 elements – earth, air, fire and water (Continuous Theory) 4 elements – earth, air, fire and water (Continuous.

Atomic Structure. 1. Democritus: Around 300 BC, a Greek philosopher, Democritus stated that everything is made up of tiny, invisible particles He said.

Chapter 4 Atomic Structure.

History of the Atom Democritus Democritus: It was 400 BC when he came up with the idea that matter could not be divided indefinitely. This lead to the.

Chapter 4 Atomic Structure

Development of Atomic Theory Ancient Times | Dalton's Postulates | Thomson's Discovery of Electron Properties | Rutherford's Nuclear Atom | Bohr's Nuclear.

Early Ideas about Matter. atom u The smallest piece of the element with all the chemical properties of the element u an old and new idea.

Describe the mass, charge, and location of protons, neutrons, and electrons in atoms. S-105.

History of the Atom 440 BC – Democritus and Leucippus developed the original atomic concept –There exist indivisible particles called atoms (“a” meaning.

History of the atom: History of the atom: Changing atomic models.

1.3 Early Models of the Atom pp Ancient Models of the Atom Democritus: he stated that there must be a smallest particle, which he called an.

The Changing Model of the Atom

The History of Atoms Not the history of the atom itself, but the history of the idea of the atom.

The elements  The Greeks were the first to explain why chemical changes occur.  They proposed that all matter was composed of four substances: fire,

Matter & The Atom. Matter The term matter describes all of the physical substances around us: your table, your body, a pencil, water, and so forth.

Brief History of Atomic Theory. 1 st atomic models In 400 BC, the model looked like a solid indivisible ball In 400 BC, the model looked like a solid.

5.1 Developing the Atomic Theory pp Learning Goals: Know who the key atomic theorists are & what their contribution was Know the model of.

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

The History of the Atom. Aristotle  Aristotle was the first scientist that we have record of questioning what stuff was made of.  What did he think?

Chapter 4. Atom Smallest particle of an element that retains its chemical identity Atoms of the same element cannot be separated chemically because they.

Models of the Atom. Ancient Greece 300 BC in Greece School of thought that matter is made up of tiny indivisible, invisible, indestructible, fundamental.

+ ATOMIC THEORY. + Democritus Atom He was said to be the first step toward the current atomic theory. Hypothesized all matter is composed of tiny particles.

Smallest particle of an element that retains the properties of the element.

History of the Atom. Atoms and Elements Any material that is composed of only one type of atom is called an element. An atom is the smallest particle.

The Changing Model of the Atom From Democritus to Bohr.

The Changing Model of the Atom. Aristotle 400 BCE claimed that there was no smallest part of matter different substances were made up of different proportions.

S. Aldrich HISTORY OF THE ATOM 460 BCE Democritus develops the idea of atoms He believed that you could cut objects in half, over and over again,

Atomic Theory and the Atomic Model. Objectives Describe evidence that Greek philosophers used to develop the idea of atoms. Distinguish between a scientific.

Presentation transcript:

A.1 - In which you will learn about: Democritus Lavoisier Dalton Thomson Unit 3: Quantum Mechanics Section A: History of Atomic Theory

Early Humans Believed…

Empedocles ( BCE) Four Elements Theory: Earth, air, fire, water Main Problem: No matter how many times you break down a stone (or other piece of matter), the pieces never resemble the four elements of earth, air, fire, or water Main Importance: Among the first theories to suggest that pure materials are made up of a combination of “elements”

Democritus ( BCE) “Atomos” (Greek for “indivisible”) Theory: If you take a stone and cut it in half, each half has the same properties as the original stone. If you continued to cut the stone into smaller and smaller pieces, at some point you would reach a piece so tiny that it could no longer be divided. Democritus suggested that atomos were eternal and could not be destroyed. Democritus theorized that atomos were specific to the material that they made up, EX: The atomos of stone are unique to stone and different from the atomos of other materials, such as fur.

Antoine Lavoisier (1778) Conducted many experiments with air Burned substances such as phosphorus and sulfur in air, and showed that they combined with air to make new materials. These new materials weighed more than the original substances, and Lavoisier showed that the weight gained by the new materials was lost from the air in which the substances were burned. From these observations, Lavoisier established the Law of Conservation of Mass, which says that mass is not lost or gained during a chemical reaction.

John Dalton (1803) Dalton’s Atomic Theory: All matter is composed of indivisible particles called atoms. Dalton pictured atoms as tiny billiard-ball-like particles in various states of motion. This postulate is violated by subatomic particles – protons, neutrons, and electrons. All atoms of a given element are identical. Dalton characterized elements according to their atomic weight; however, when isotopes of elements were discovered in the late 1800s this concept changed. Chemical reactions involve the combination of atoms, not the destruction of atoms. This is largely based on Antonie Lavoisier’s law of conservation of matter. When elements react to form compounds, they react in defined, whole-number ratios. The experiments that Dalton and others performed showed that reactions are not random events; they proceed according to precise and well-defined formulas.

Dalton’s Model of the Atom: Billiard Ball

J.J. Thomson’s Discovery of the Electron Used a cathode ray tube to conduct experiments

Cathode Ray Tube Vocabulary

What is a cathode ray? “Cathode rays” occur when electricity is applied to the cathode of the tube and the electricity moves through the gas inside the tube to get to the anode. The beam of electricity causes the gas in the tube to glow. When a magnet is placed near the beam, the beam bends towards the magnet! This means the beam is negative! (We now know that electricity is the flow of electrons, so this makes perfect sense)

Thomson’s Fame His experiments prompted him to make a bold proposal: these mysterious rays are streams of particles much smaller than atoms He called these particles "corpuscles," and suggested that they might make up all of the matter in atoms. It was startling to imagine a particle residing inside the atom-- most people thought that the atom was indivisible (according to Dalton), the most fundamental unit of matter. Thomson also theorized that if the tiny particles were negative, then they must be surrounded by positive charge for balance

Thomson’s Model of the Atom: Plum Pudding

HOMEWORK QUESTIONS 1) Define atom using your own words. 2) Summarize Dalton’s atomic theory. 3) Explain how Dalton’s theory of the atom and the conservation of mass are related. 4) Describe the structure of a typical atom. Identify where each subatomic particle is located. 5) Evaluate the experiments that led to the conclusion that electrons are negatively charged particles found in all matter (you may want to use more outside resources for this).