Download Monday, September 29

DAILY QUESTION
September 29, 2008
1. Who’s atomic
theory is considered
the foundation for the
modern atomic
theory?
Agenda
9/29/08
• Daily Question
• Chapter 4 - Introduction
Assignments:
1. No Assignments Tonight.
~ Year
~ Scientist
~ Contribution
Atomic Theory Timeline
1800
500 BC
1935
~ Year
~ Scientist
~ Contribution
•Democritus: In
4th century BCE
(460 BC), he
suggested that
the universe was
made of invisible
units called
atoms. The word
atom is derived
from the Greek
word meaning
“unable to be
divided.”
Atomic Theory Timeline
Dmitry
Medeleyev
– In 1871,
he
revealed
the basic
importance
of atomic
weights
and of
nuclear
structure.
•Sir Ernest
Rutherford – In
1909, he
constructed the
first nuclear
model of the
atom, a
cornerstone of
present-day
physics. In
1919, he
proved the
nucleus could
be breached
•Erwin Schrodinger:
Building on de
Broglie's idea that
electrons act like
•Louis de Broglie: He
waves in some
proposed in 1924 that
situations, he
electrons could behave as developed the basic
waves under some
equation of quantum
conditions, a finding that
mechanics in 1926
helped scientists
understand that the atom
didn't behave like the solar
•Werner Heisenberg:
system because electrons
In 1927 he proposed
do not move in regular
that it is impossible to
orbits.
know the position and
velocity of an electron
at the same time; this
concept is called the
.
uncertainty principle.
1800
500 BC
•John Dalton:
In 1808
proposed the
atomic theory.
According to
Dalton, all
atoms of a
given element
were exactly
the same and
the atoms
could join to
form
compounds.
•Sir J.J.
Thomson – In
1897, the
English physicist
explained the
nature of the
electron.
1935
•Niels Bohr: In 1913,
he proposed a model
of the atom with
electrons orbiting the
nucleus similar to the
planets revolving
around the sun. The
orbits of electrons
depend on their
energy, and
electrons can jump
from one energy
level to another; and
energy travels in
•James
Chadwick and
E.S. Bieler: They
proposed in
1921 that a
strong force held
the nucleus
together.
•In 1932,
Chadwick
discovered the
neutron, a
particle with no
discrete quantities.
electrical charge.
Max Born: Working with
Heisenberg in 1927,
Born modified
Schrodinger's equation
of quantum mechanics.
His idea helped
scientists develop the
model of an atom with a
nucleus surrounded by
electrons at different
locations when they are
in different energy states.
Developing the Atomic Theory
• Democritus: In 4th century BCE (460 BC),
he suggested that the universe was made
of invisible units called atoms. The word
atom is derived from the Greek word
meaning “unable to be divided.”
• John Dalton: In 1808 proposed the atomic
theory. According to Dalton, all atoms of a
given element were exactly the same and
the atoms could join to form compounds.
Developing the Atomic Theory
• Dmitry Medeleyev – In 1871, he revealed the
basic importance of atomic weights and of
nuclear structure.
• Sir J.J. Thomson – In 1897, the English physicist
explained the nature of the electron.
• Sir Ernest Rutherford – In 1909, he constructed
the first nuclear model of the atom, a
cornerstone of present-day physics.
Developing the Atomic Theory
• Niels Bohr: In 1913, he proposed a model of the atom
with electrons orbiting the nucleus similar to the planets
revolving around the sun. The orbits of electrons depend
on their energy, and electrons can jump from one energy
level to another; and energy travels in discrete
quantities.
• James Chadwick and E.S. Bieler: They proposed in
1921 that a strong force held the nucleus together.
• Louis de Broglie: He proposed in 1924 that electrons
could behave as waves under some conditions, a finding
that helped scientists understand that the atom didn't
behave like the solar system because electrons do not
move in regular orbits.
Developing the Atomic Theory
• Erwin Schrodinger: Building on de Broglie's idea that
electrons act like waves in some situations, he
developed the basic equation of quantum mechanics in
1926.
• Werner Heisenberg: In 1927 he proposed that it is
impossible to know the position and velocity of an
electron at the same time; this concept is called the
uncertainty principle.
• Max Born: Working with Heisenberg in 1927, Born
modified Schrodinger's equation of quantum mechanics.
His idea helped scientists develop the model of an atom
with a nucleus surrounded by electrons at different
locations when they are in different energy states.
Atoms (page 104-105)
• The smallest part of an element that still
has the element’s properties
• Combine to make molecules
– Examples: H2O
• Whether 1 molecule or billions, they are
always the same: 2 hydrogen to 1 oxygen
What’s in an Atom? (page 106)
Subatomic particles
Proton Neutron Electron
Positive Charge
Negative Charge
No Charge
Found in Nucleus
Found in Nucleus
Found surrounding Nucleus
Very little mass
Same mass as a proton
Same mass as a neutron
Same size as a proton
Same size as a neutron
Very small size