Download Chapter 18 Atoms and Elements

Chapter 18
Atoms and Elements
18.1 Atomic Structure
Goals
*What are the parts of an atom?
*How did the work of numerous
scientists lead to the current model
of an atom?
I. All matter (everything you see,
hear, touch, smell and taste) is
formed from __________, either
by themselves or combined in
_______________.
A. Size
1. Atoms are tiny!!! A dust speck
contains more than___________.
B. Parts
1. Atoms contain _____ __________ particles:
they are: __________________________
2. Nucleus- ____________________
___________________.
3. The _______________ move in
space around the nucleus.
Their location ___________ be
determined at any one time.
C. Subatomic particles have charge and mass:
Particle
Charge
Mass (amu)
So...how did we find all this out?
II. Scientists Involved
A. Greek Philosophers- proposed
an atomic theory around 400 BC
which stated....all matter is made
__________________________
______.
B. Democritus- Named the atom
from the Greek word _______,
meaning "____________".
C.
1.
John Dalton's Atomic Theory (1808)
Elements are made of ___________
2.
Atoms of the same element are ____________.
3.
Atoms of __________________________.
4.
Atoms are ____________ by chemical reactions.
5. Compounds are formed by joining ___________.
6. Compounds are defined by
number, type and proportion of
atoms.
D.
Joseph John Thomson (1904)
1. Discovered the ___________
and determined that they have a
____________charge.
2. He knew that atoms were
___________, so proposed that
the atom was a ___________ with
negative electrons embedded in it.
E. Ernest Rutherford (1911)
1. Conducted the "______________" experiment.
2. Hypothesized that atoms are made _________
________________________
3. Introduced the nucleus- ________________.
F. Niels Bohr (1885- 1962)
1. Conducted experiments to
update Rutherford's model.
2. Stated that ____________
move around the nucleus in
____________
G. James Chadwick (1932)
1. Discovered the _______________
2. Introduced the __________________ _____________________________.
3. The cloud represents _________ location
of an electron.
Comparing Atoms
Goals:
* What is the difference between
atomic number, mass number and
atomic mass?
*How do we create an accurate
atom diagram of any element? How
is an isotope diagram different?
A. Atomic Number
1. The atomic number is the
number of
_______________________
2. The atomic number
___________
the type of element you have.
Ex. 7 protons= _____________
15 protons= _____________
ALWAYS!!
3. The periodic table is ordered by the
number of ________________.
*It starts with 1 (hydrogen) and ends with
118 (ununoctium)
B. Mass Number vs. Atomic Mass
1. Mass number- the total number of _______________ (in
the nucleus).
* Atoms of the same element ________ have different number
of ___________, which means the mass can vary.
2. Atomic Mass- the average of ________________ of an
element.
A
i
m
to
c
ss
a
m
The mass number would be 31
C. Isotopes
1. Isotope- ________ of the
same element that have
_________________________.
Example: Carbon
Carbon-12
Carbon-13
protons=
neutons=
D. Strong Nucleus Force
The nucleus contains positive protons and
neutral neutrons, so what holds it
together?
It is held together by __________
________________________
...called the strong ______________.
E. Energy Levels
1. Electrons are arranged into
_____________ that hold a
specific amount of electrons.
2. The energy levels make up the
electron cloud.
3. The ___________ out the
electrons are, the _______ their
energy state.
4. ____________ electronselectrons in the _________ region
of the electron cloud- the
_________ involved in bonding.