Atomic Theory.

Slides:

Advertisements

Similar presentations

Atomic Theory Timeline

Advertisements

First 5 min of class Identify the following as a molecule, compound, element, or/and an atom. KCl 200 copper atoms O2 C2H4 He.

ATOMIC STRUCTURE AND HISTORY

Atomic Theory “History of. . . ”.

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

Atomic Structure Timeline

Atomic Structure.

AIM: Models of the Atom DO NOW:

HW for Next Class:  Read pages  Worksheet: 5.2 (Structure of Nuclear Atom)  Quiz: Next time.

Atomic Theory Mr. Tollefson Chemistry Class. Introduction Students will be introduced to the atom and the development of the atomic theory from ancient.

The Atomic Model Chem 9.

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

Atomic Structure Timeline Read Around the Room. Democritus (400 B.C.) Proposed that matter was composed of tiny indivisible particles Not based on experimental.

Unit: Atomic Structure

Chemistry Sheds Light on Our Lives Unit 4 Atoms and Light

Chapter 4: Discovery of Atomic Structure. Prentice Hall © 2003Chapter 2 The Discovery of Atomic Structure An ancient Greek named Democritus was the first.

Atomic Structure.

TITLE The Development of Atomic Theory. Early Ideas Democritus—Greece 400 B.C. His idea:  There was a limit to how far you could divide matter. You would.

Atomic Theory and Structure Chapters 4-5 Atomic Theories Democritus ~ 400 BC believed that atoms were indivisible and indestructible Dalton ~ 1800’s.

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

Chemistry AI Chapter 4 A. Atom (Section 4.1) 1. Democritus (460B.C.-370B.C.) The smallest part of an element that retains its identity during a chemical.

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

The Evolution of the Model of the Atom

The Chemical Behavior of Atoms Day 1. Curriculum  Big Idea: Atomic theory is the foundation for the study of chemistry.  Concept: Energy is absorbed.

Modern Atomic Theory Grade 9 Science Chemistry.

CHAPTER 4 ATOMIC STRUCTURE.  Define Democritus’s ideas about atoms  Explain Dalton’s Atomic Theory  Identify what instrument is used to observe individual.

Chapter 4 – Atomic Structure

Unit 2 - Lecture 1: Structure of the Atom

Solid, homogeneous, indestructible and indivisible (400 BC)

Do Now: 1.On the blank side of an index card, draw a picture of an atom. 2.On the other side of the index card, write down things that you know about atoms.

History of the Atomic Model

A Brief History of the Atomic Theory. 460 B.C. : Democritus Greek Philosopher Proposed that matter cannot be broken down indefinitely At some point you.

The Atom Chapters 4-5 Atomic Theories Democritus ~ 400 BC believed that atoms were indivisible and indestructible Dalton ~ 1800’s Developed through experiments.

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

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.

The Structure of the Atom

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

Atoms The Development of Atomic Theory. Atoms An atom is the smallest piece of an element that still retains all of the properties of that element These.

Atomic Structure.  Democritus (460 BC – 360 BC)  Ancient Greek philosopher ▪ No experiments performed!  Major Contribution: The Atom ▪ He proposed.

Atomic Theory Mr. Tollefson Chemistry Class. Introduction Students will be introduced to the atom and the development of the atomic theory from ancient.

1 The History of Atomic Theory A long and winding road Section 4.1.

Atomic Structure Timeline

Models of the Atom SCH3U.

Origin of the idea of atom…

Atomic Structure Timeline

3.1 – Atomic Theory and the History of the Atom

Chapter 4 Atomic Structure 4.2 Structure of the Nuclear Atom

Models of the Atom.

Chapter 4 Atomic Structure 4.2 Structure of the Nuclear Atom

Origin of the idea of atom…

BELLWORK 9/11/17 What is the atom?

Atomic Structure Timeline

Atomic Structure.

Atomic Structure Timeline

The History of Atomic Theory

Atomic Structure Timeline

Chapter 4 Atomic Structure 4.2 Structure of the Nuclear Atom

Chapter 4 Atoms 1. Atomic Structure Timeline

Atomic Structure Timeline

History of The Atomic Theory

Chapter 4 Atomic Structure 4.2 Structure of the Nuclear Atom

Chapter 4 Atomic Structure 4.2 Structure of the Nuclear Atom

Chapter 4 Atoms.

Atomic Theory The idea that matter is made up of atoms, the smallest pieces of matter.

Atomic Structure Timeline

Chapter 4 Atoms.

Atomic Structure Timeline

Presentation transcript:

Atomic Theory

Greek Model - Fourth and Fifth Centuries BC • The word atom is from the Greek word atomos, which means indivisible or uncut • This was the original model of the atom • It viewed the atom as the smallest indivisible particle of matter • This theory was never verified by experiments and was discarded

Dalton’s Atomic Theory John Dalton (1766-1844) 4 main points: 1. All elements are composed of tiny indivisible particles called atoms. 2. Atoms of the same element are identical. The atoms of any one element are different from those of any other element.

3. Atoms of different elements can combine with another in simple whole number ratios to form compounds. 4. Chemical reactions occur when atoms are separated, joined, or rearranged. However, atoms of one element cannot be changed into atoms of another element by a chemical reaction.

Which parts of Dalton’s theory are still considered to be true? 2. The atoms of any one element are different from those of any other element. 3. Atoms of different elements can combine with another in simple whole number ratios to form compounds. 4. Chemical reactions occur when atoms are separated, joined, or rearranged. However, atoms of one element cannot be changed into atoms of another element by a chemical reaction.

Which parts of Dalton’s theory are no longer believed to be true? 1. All elements are composed of tiny indivisible particles called atoms. • We now know that atoms are divisible, there are particle found within the atom: protons, neutrons, and electrons. 2. Atoms of the same element are identical. • Isotopes are atoms of the same element that have different mass numbers because of different numbers of neutrons, therefore, all atoms of the same element are NOT identical.

Thomson’s Model of the Atom Joseph John Thomson (1856 – 1940)

What did Thomson conclude about electrons? Thomson determined that electrons were a fundamental particle of matter, that all electrons were identical regardless of the element, and that they carry a negative charge.

Briefly describe Thomson’s model of the atom. Thomson viewed the atom as a sphere of uniform positive charge with negative electrons embed throughout.

Rutherford’s Model of the Atom – Ernest Rutherford (1871 – 1937)

Working with radium (a radioactive element) Rutherford discovered that the invisible rays were actually composed of three different rays: alpha (positively charged), beta (negatively charged), and gamma (uncharged) rays.

Gold Foil Experiment Using alpha particles, Rutherford investigated the scattering of these particles by thin sheets of gold foil.

What were the expected results of the Gold Foil Experiment, and how did the actual results differ from expected? Rutherford expected all of the alpha particles to go straight through the gold foil without any change in direction. This is not what occurred. Most of the alpha particles did not have any change in direction, but some were deflected and some were reflected.

Rutherford used these results to design his own model of the atom.

Rutherford assumed that there must be something within the atom, which caused the alpha particles to be deflected or reflected. Rutherford suggested that an atom had a nucleus or centre in which the positive charge and most of the mass were located. This nucleus occupied only a tiny portion of the volume of the entire atom. The electrons were located outside the nucleus. This model of the atom is often called the “nuclear” atom.

The Bohr Model of the Atom Niels Bohr (1885 – 1962)

Bohr investigated the spectra of hydrogen Bohr investigated the spectra of hydrogen. He determined that hydrogen produced a line spectra with four distinct lines in the visible spectrum.

Because hydrogen produced line spectra, Bohr explained that the energy of these lines corresponded to the energies released when an electron at a higher energy level returned to a lower energy level. The difference in energy between two energy levels was emitted as electromagnetic radiation with a specific wavelength.

The central nucleus, with electrons in motion around the nucleus, is still retained in the Bohr model of the atom. Bohr provided more information about the motion of the electrons.

Erwin Schrodinger Developed a mathematical equation describing the location and energy of electrons in atoms The quantum mechanical model also places electrons in energy levels, similar to Bohr’s model

The quantum mechanical model is different in the following ways: The exact path of the electron cannot be defined, only the probability of the electron’s location. This is described as an electron cloud. The electron can be found anywhere in the cloud Within energy levels, there are sublevels called orbitals. At higher energy levels there are more than one type of orbital.