Name: ___________________________________ Date: _____________ Period: ______
Chapter 4.1 Notes
A. Studying the structure of _______ poses a problem due to the
fact that they are extremely _______. Even with a _____________
scientists cannot see the ____________ of an ________. Since the
structure of atoms cannot be seen ___________ evidence must be
used to develop ___________ of atoms.
B. Ancient Greek Models of Atoms
A. ______________ believed that all _________ consisted of
extremely small _____________.
1. He called these particles _________.
2. He thought they could not be _____________.
3. He thought there were _____________ types of
________ with specific sets of _________________.
Ex. Atoms in _________ were ________ and __________,
but the atoms in ________ were ________ and _________.
B. Aristotle
1. Believed there was ___ _______ to the number of
times _________ could be _______________.
2. All _________________ were built up from four
_____________: _______, ______, ______, and ____.
3. These elements had four _______________: ______,
_______, _____, and _____.
C. John Dalton
A. John Dalton was born in England in 1766. He became a
teacher and spent his spare time doing experiments.
B. Correctly concluded that a _____ consists of individual
_______________.
C. Gathered evidence of the _____________ of ________ by
measuring the ____________ of elements that combine when
________________ form.
D. The ________ of the ____________ of the elements in the
compound is always the _______________.
E. _________________ have a fixed ___________________.
Ex. When magnesium burns it _____________ with oxygen.
_________ of magnesium combines with _____________ of
Name: ___________________________________ Date: _____________ Period: ______
oxygen. ______of magnesium combines with _______ of oxygen.
D. Dalton’s Atomic Theory
A. ________ is made up of individual _____________ called
______________, which cannot be ________________.
1. All _____________ are composed of ________.
2. All ______ of the ____ element have the same ____,
and atoms of ________ elements have different _____.
3. _________ contain atoms of _____ than one ______.
4. In a particular _________, atoms of different
____________ always combine in the _________ way.
B. While this theory was _____ perfect it was not _________
but revised to __________ for new ________________.
Pic: Dalton represented __________ as solid ________. Each
type of _______ is represented by _____, _______ spheres
with a different _________.
C. What did Dalton notice that all compounds have in
common?
______________________________________________________
____________________________________________________
E. Joseph John Thomson (1856-1940), J.J. Thomson, used an
_________________ current to learn more about _________.
A. The device used to create an electric current was a ______
____ with most of the ____ vacuumed out sealed with a
________ disk on each end. When the electric current is
turned on one ________ becomes ______________ charged
while the other disk becomes ________________ charged.
This created a glowing ________ in the glass tube.
B. Thomson hypothesized that the _______ was a stream of
________ particles that interacted with the ____ in the tube
and caused the air to _________.
C. Thomson found, in an experiment, that the _________ of
charged ___________ was attracted to a ________________
charged plate.
D. He __________________ that the particles came from
___________ atoms.
Name: ___________________________________ Date: _____________ Period: ______
E. Thomson’s experiments provided the ______ evidence
that ________ are made of even _____________ particles.
F. This changed how scientists thought about atoms.
G. Thomson revised ____________ model to account for
these _______________ particles.
F. Thomson’s Model
A. An atom is _____________, meaning it has neither a
____________ nor a positive charge. However, Thomson
knew from his experiments that _________ contained
negatively charged _____________.
B. How can an atom contain negative particles and still be
neutral?
C. Plum Pudding Model (Chocolate Chip Ice Cream)
1. In Thomson’s model the ___________ charges were
______ scattered throughout an _____ filled with a
_____________ charged _________ of matter.
2. Think of _____________ ________ as negative
particles and the ____ ________ as a positively
charged mass of ________. With the chocolate chips
spread _______ throughout the ice cream the
________ of the chocolate chips and ice cream ___________
each other out and create an overall ___________ charge.
D. What evidence did Thompson’s experiments provide?
________________________________________________.
G. Ernest Rutherford (1871-1937)
A. Surprised by _____________ results that lead to important
_________________.
B. Discovered that _____________ emits fast moving
________________ that
have a _____________ charge.
He named these particles ___________ particles.
C. Rutherford’s experiment consisted of sending a ______ of
alpha particles through a thin sheet of ______ ___________.
D. He hypothesized, based on ____________ model, that the
Name: ___________________________________ Date: _____________ Period: ______
_____ and ______ of the alpha particles traveling through the
gold foil would be too ________ to change the _____ of the
particles. The particles would travel ______ through the gold
foil and ________ a screen that would ______ ___ when hit.
E. Some of the ____________ that hit the gold foil were
____________. He found that his hypothesis was _______.
F. This led Rutherford to believe that the ___________
charge of an _________ is not __________ spread
throughout the atom.
G. The ____________ charge is _______________ in a very
small, central area called the _______________.
H. The particles that were ________________ came close to
a ___________, while the ones that traveled ___________
through did not.
I. Rutherford’s __________ showed that all of the ________
charged particles of an _______ are concentrated in its
____________ not spread ______ out like Thomson’s model.
Scientist
Evidence
Model
Ratio of masses
Deflected Beam of charged
particles
Rutherford
Nucleus
Demonstration: Atomic Theory Alcohol Swab
1. Where does the alcohol go? __________________________
___________________________________________________
2. Does it leave the paper all at once in one big chunk? _______
___________________________________________________
3. How does this observation show that the alcohol must
actually be made of individual particles? ________________
___________________________________________________
___________________________________________________