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Chapter 4: Atomic Structure
Laboratory Chemistry
You cannot see them, yet they make up everything…
THE ATOM

An atom is the smallest particle of an __________________________________________
_____________________________________________________________________________________.
Theories Over Time

The modern model of the atom has developed ___________________ over time as many
philosophers and scientists ________________________________________________.
Early Models of the Atom

Let’s learn about the dead guys!
Democritus

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Democritus was a ___________________________________________________________ who lived
from 460 – 370 B.C.
Democritus was the first __________________________________________________________________
Democritus believed that there where particles called “___________________”, which he
believed ______________________________________________________________________________.
“Atomos” in Greek means ________________________
Anton Lavoisier (late 1700s)

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Developed _______________________________________________________________________________
Matter cannot be ___________________ nor ____________________
Joseph Proust (late 1700s)
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Developed ________________________________________________________________________________
The particles of a pure substance are __________________________________________________.
Dalton’s Atomic Theory (1803)

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John’s Dalton was ________________________________________________.
Although many philosophers and scientists before him developed ideas of the atom,
John Dalton was ____________________________________________________________________________
because Dalton was the first to use _____________________________________________.
Dalton’s Atomic Theory
1.) All elements are ____________________________________________________________________________
______________________________________________________________________________________________
2.) Atoms ______________________________________________________________________________________
3.) Atoms of different elements can __________________________________________________________
_______________________________________________________________________________________________
4.) Chemical reactions occur when atoms ________________________. Atoms of one element
are never ___________________________________________________________________________________.
Dalton’s Atomic Theory

Dalton’s atomic theory can be linked back to the ideas of _________________________
______________________________________________________________
Subatomic Particles
 Much of Dalton’s theory remains true, however ________________________
__________________________________________________________________.

Subatomic particles refers to the particles ___________________________________________.
o __________________________
o __________________________
o __________________________
Electricity and the Atom
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Ben Franklin (1700s)
o First to determine that there were ____________________________________________
_________________________ charges.
Michael Faraday (1839)
o Suggested that the structure of atoms _________________________________________
_____________________________________________.
Electrons
 Electrons _______________________________________________________________

JJ Thompson was the first to ___________________________________________________________
using a __________________________________.

JJ Thompson’s atomic model was called the plum pudding model
Cathode Ray Tube
Discovery of the Nucleus
 Rutherford’s __________________________________________Experiment
 Rutherford shot a beam of alpha particles (______________________________________________)
at a very thin sheet of ___________________________.

Rutherford expected the alpha particles to _______________________________________________
with a slight deflection from the positive charges spread throughout the gold foil

Most of the particles went through the gold foil but Rutherford was surprised to find
a ___________________________________________________________________________________.
Rutherford’s Atomic Model
 Rutherford determined that…
 ___________________________________________________________________________________.
 The positive charge and almost all the mass are _______________________________________
_________________________________________________________________.
The Nucleus
 The nucleus is composed of __________________________ and _____________________________
 Protons have a _________________________________
 Neutrons have _________________________________ (________________________)
 Therefore… the nucleus has a _________________________________________________________
 Almost all of an atom’s mass ____________________________________________________________.
Properties of Subatomic Particles
Particle
Symbol
Relative
Charge
Actual Mass
Electron
9.11 x 10-28
Proton
1.67 x 10-24
Neurton
1.67 x 10-24
Relative Mass
What makes atoms different if they are all made up of protons, electrons, and neutrons?

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__________________________________________________________________________________________.
Most importantly, the number of ____________________________________________________
___________________________________________________.
Atomic Number
 Elements are different because ________________________________________________________
__________________________________________________________.
 The atomic number = __________________________________________________
Mass Number
 The mass number = _______________________________________________________
 Mass of electrons is ____________________________________
Calculating number of Protons, Neutrons, and Electrons
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Atomic number and Mass number can be found on the periodic table
Number of Protons = ____________________________________
Number of electrons = ____________________________________
Number of Neutrons = ____________________________________
Carbon
p=
n=
e=
Aluminum
Lithium
Hydrogen
Silicon
p=
p=
p=
p=
n=
n=
n=
n=
e=
e=
e=
e=
Isotopes
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An isotope is an atom with the same number of protons, but __________________________
____________________________________________________
Therefore…. Isotopes have different ____________________________________
Atomic Mass
o The atomic mass of an element is the ________________________________________
_______________________________________________________
o This is why the atomic masses on your periodic table are
_______________________________________________________