Transcript Chp4Sec1and2

Chapter 4 Elements and the Periodic Table
Section 1:
Introduction
to Atoms
How did atomic theory develop and change?
Chapter 4 Elements and the Periodic Table
Section 1:
Introduction
to Atoms
How did atomic theory develop and change?
Atomic theory grew as a series of models that developed
from experimental evidence. As more evidence was
collected, the theory and models were revised.
Chapter 4 Elements and the Periodic Table
Atomic Theory and Models
Dalton thought that atoms were like smooth, hard balls that
could not be broken into smaller pieces.
Chapter 4 Elements and the Periodic Table
Atomic Theory and Models
Thomson suggested that atoms had negatively charged
electrons embedded in a positive sphere.
Chapter 4 Elements and the Periodic Table
Rutherford’s Gold Foil Experiment
Rutherford was surprised that a few particles were deflected
strongly. This led him to propose an atomic model with a
positively charged nucleus.
Chapter 4 Elements and the Periodic Table
Later Atomic Models
Through the first part of the twentieth century, atomic models
continued to change.
Chapter 4 Elements and the Periodic Table
Section 1:
Introduction to Atoms
What is the modern model
of the atom?
Chapter 4 Elements and the Periodic Table
Section 1:
Introduction to Atoms
What is the modern model
of the atom?
At the center of the atom is a tiny,
massive nucleus containing
protons and neutrons.
Surrounding the nucleus is a cloudlike region of moving
electrons.
Chapter 4 Elements and the Periodic Table
Modern Model of an Atom
This model of a carbon atom consists of positively charged
protons and neutral neutrons in a nucleus that is surrounded
by a cloud of negatively charged electrons.
Chapter 4 Elements and the Periodic Table
Particles in an Atom
An atom is composed of positively charged protons, neutral
neutrons, and negatively charged electrons. Protons and
neutrons are about equal in mass. An electron has about
1/2,000 the mass of a proton or neutron.
Chapter 4 Elements and the Periodic Table
Isotopes
Atoms of all isotopes of carbon contain six protons and six
electrons, but they differ in their number of neutrons. Carbon12 is the most common isotope.
Chapter 4 Elements and the Periodic Table
End of Section 1:
Introduction to Atoms
Chapter 4 Elements and the Periodic Table
Section 2:
Organizing the
Elements
How did Mendeleev discover
the pattern that led to the periodic table?
Chapter 4 Elements and the Periodic Table
Section 2:
Organizing the
Elements
How did Mendeleev discover
the pattern that led to the periodic table?
Mendeleev noticed that a pattern of properties appeared when
he arranged the elements in order of increasing atomic mass.
Chapter 4 Elements and the Periodic Table
Section 2:
Organizing the
Elements
How are the elements organized in the modern periodic table?
Chapter 4 Elements and the Periodic Table
Section 2:
Organizing the
Elements
How are the elements organized in the modern periodic table?
The properties of an element can be predicted from its location
on the periodic table.
Chapter 4 Elements and the Periodic Table
The Periodic Table
Elements are organized into rows and
columns based on their atomic number.
Chapter 4 Elements and the Periodic Table
The Periodic Table
Elements are organized into
rows and columns based on
their atomic number.
Chapter 4 Elements and the Periodic Table
The Periodic Table
Elements are organized into
rows and columns based on
their atomic number.
Chapter 4 Elements and the Periodic Table
Finding Data on Elements
Each square in the periodic table lists four pieces of
information: an element’s atomic number, chemical symbol,
name, and atomic mass.
Chapter 4 Elements and the Periodic Table
End of Section 2:
Organizing the
Elements