Chapter 2 Atoms and Elements - PowerPoint PPT Presentation

1 / 15
About This Presentation
Title:

Chapter 2 Atoms and Elements

Description:

fundamental building block of all matter. origin in Greek philosophy. Democritus (460-370 BC) atomos = indivisible. no experimental evidence ... – PowerPoint PPT presentation

Number of Views:36
Avg rating:3.0/5.0
Slides: 16
Provided by: markj56
Category:

less

Transcript and Presenter's Notes

Title: Chapter 2 Atoms and Elements


1
Chapter 2Atoms and Elements
  • Structure of the Atom
  • Isotopes and Atomic Mass
  • The Mole
  • The Periodic Table

2
I. Structure of the Atom
  • The Atom
  • fundamental building block of all matter
  • origin in Greek philosophy
  • Democritus (460-370 BC)
  • atomos indivisible
  • no experimental evidence
  • Modern Atomic Theory John Dalton (1766-1844)
  • Combined
  • Law of Definite Proportions
  • Law of Conservation of Matter
  • Law of Multiple Proportions

3
Postulates of Daltons Atomic Theory (1808)
  • All matter is made of atoms. These indivisible
    and indestructible objects are the ultimate
    chemical particles.
  • All atoms of a given element are identical, both
    in mass and in properties. Atoms of different
    elements have different masses and different
    properties.
  • Compounds are formed by combination of two or
    more different kinds of atoms. Atoms combine in
    the ratio of small whole numbers, for example,
    one atom of A with one atom of B, or two atoms of
    A with one atom of B.
  • Atoms are the units of chemical change. A
    chemical reaction involves only combination,
    separation, or rearrangement of atoms. Atoms are
    not created, destroyed, divided into parts, or
    converted into other kinds of atoms during a
    chemical reaction.

4
B. Subatomic Particles
  • The electron
  • JJ Thompson (1897) proved existence of
    electrons and calculated mass-to-charge ratio

5
(No Transcript)
6
  • Robert Millikan (1911-1913) oil drop experiment
    determined charge of electron

7
  • The proton
  • Eugen Goldstein (1886) canal rays
  • Ernest Rutherford (1919)
  • The neutron
  • James Chadwick (1932)

8
C. Our Modern Picture of the Atom
  • Rutherford Gold Foil Experiment (1910)
  • Charge and mass concentrated in very small space
    (nucleus)

9
Football stadium analogy
  • Our Representation of the Atom

10
II. Isotopes and Atomic Mass
  • Isotopes
  • atoms of the same element with differing numbers
    of neutrons

11
  • How do we represent the size of an atom?
  • standard unit atomic mass unit (amu)
  • Atomic Mass
  • weighted average of all naturally occurring
    isotopes of an element

12
III. The Mole
  • One mole
  • number of atoms in exactly 12 grams of carbon-12
  • 6.022 ? 1023 (Avogadros number)
  • Molar Mass (M)
  • mass of 1 mol of atoms of an element
  • equals the atomic mass in grams

13
One mole quantities of common elements
14
III. The Periodic Table
  • arrangement of elements according to repeating
    (periodic) properties
  • elements listed according to atomic number

15
Transition Metals
Write a Comment
User Comments (0)
About PowerShow.com