Answer the following questions in your lab book:
1. What is all stuff made out of?
2. What is the previous answer made out of? What is the simplest form you can get?
3. Draw an example of it

9.9 Research Papers turned into back tray
9.9 IRB Paperwork due – make sure it is all attached with a paperclip & handed to me
9.12 Materials & Methods due online
9.19 Journal Check & Experimental Design

http://learn.genetics.utah.edu/content/cells/scale/
So what does an atom really look like?
How small is it?
http://ed.ted.com/lessons/just-how-small-is-an-atom

Explain & expound on one of the atomic theories that led to our understanding of the atom today.
Include: the name of the theory
Scientist
How they came up with the theory (key facts)
Diagram or model of their atom

Studying:
Independent studying
Music is ok
Reading or working on assignments
Computers – wait for me to get
Science Fair ppl finished

9.11 Warm Up – answer the following questions as best as possible
1. Draw a simple Bohr model for one the following atoms:
2. What is the atomic number?
3. What is the atomic mass?
4. How many protons, neutrons & electrons does it have?

1. Draw a simple Bohr model for the following atom:
1. What is the atomic number?
Atomic # = 6
2. What is the atomic mass?
Atomic mass = 12.011 amu
1. How many protons, neutrons & electrons does it have?
P = 6, N = 6, E = 6

9.9 Research Papers turned into back tray
9.9 IRB Paperwork due – make sure it is all attached with a staple, turn into tray
9.12 Materials & Methods due online
9.19 Journal Check & Experimental Design

Do you know how to apply an electron dot diagram to C & H atoms?
Could you relate it to ionic bonding or covalent bonding?

4. I can describe matter and no only the characteristics of the atom but how it relates to other atoms with bonding and properties
3. I can describe matter and the characteristics of an atom
2. I can describe the atom or matter but not how they relate
1. I know about atoms but need to review what it is composed of

What would happen if your idea of the atom was wrong? Video
Early Greeks - Democritus

Researcher Instrument Name of
Model
Sketch of
Model
Major
Discovery/
Idea

 All matter is composed of atoms
 Atoms cannot be subdivided, created, or destroyed in ordinary chemical reactions. However, these changes CAN occur in nuclear reactions!
 Atoms of an element have a characteristic average mass which is unique to that element.
 Atoms of any one element differ in properties from atoms of another element

Billiard Ball Model
All matter is composed of indivisible particles called atoms.
All atoms of the same elements are alike. Atoms of different elements different.
Compounds are formed by a combination of 2 or more atoms
Atoms cannot be created or destroyed

Video about Cathode Ray
Video on the Explanation of the Plum Pudding Model http://culturesciences.chimie.ens.fr/node/1230

Thomson concluded that the negative charges came from within the atom.
A particle smaller than an atom had to exist.
The atom was divisible!
Thomson called the negatively charged “ corpuscles, ” today known as electrons.
Since the gas was known to be neutral, having no charge, he reasoned that there must be positively charged particles in the atom.
But he could never find them.

Thomson believed that the electrons were like plums embedded in a positively charged “pudding,” thus it was called the “plum pudding” model.

 Alpha (

) particles are helium nuclei
 Particles were fired at a thin sheet of gold foil
 Particle hits on the detecting screen (film) are recorded

 Most of the particles passed right through
 A few particles were deflected
 VERY FEW were greatly deflected
Conclusions:
 The nucleus is small
 The nucleus is dense
 The nucleus is positively charged

This could only mean that the gold atoms in the sheet were mostly open space. Atoms were not a pudding filled with a positively charged material.
Rutherford concluded that an atom had a small, dense, positively charged center that repelled his positively charged “ bullets.
”
He called the center of the atom the “ nucleus ”
The nucleus is tiny compared to the atom as a whole.
Rutherford reasoned that all of an atom ’ s positively charged particles were contained in the nucleus. The negatively charged particles were scattered outside the nucleus around the atom ’ s edge.

Orbits for electrons
Energy Levels

1920’s X-Ray Diffraction
Noticed electrons behaved like particles & waves
Electrons traveled in areas of high probability in areas called ORBITALS or CLOUDS
1932 Chadwick
Discovered the neutron

Atomic model = consists of a nucleus that contains protons and neutrons, surrounded by a cloudlike region of moving electrons

Greek
Dalton
Thomson
Rutherford
Bohr
Wave
Indivisible Electron Nucleus Orbit Electron
Cloud
X
X
X
X X
X
X
X
X
X
X

Atomic number (Z) of an element is the number of protons in the nucleus of each atom of that element.
Element
Carbon
Phosphorus
Gold
# of protons Atomic # (Z)
6
15
6
15
79 79

Mass number is the number of protons and neutrons in the nucleus of an isotope.
Mass # = p + + n 0

Isotopes are atoms of the same element having different masses due to varying numbers of neutrons.
Nucleus Isotope
Hydrogen–1
(protium)
Protons Electrons Neutrons
1 1 0
Hydrogen-2
(deuterium)
1 1 1
Hydrogen-3
(tritium)
1 1 2

Atomic mass is the average of all the naturally occurring isotopes of that element.
Isotope % in nature
Carbon-12
Symbol Composition of the nucleus
12 C 6 protons
6 neutrons
98.89%
Carbon-13 13 C 1.11%
Carbon-14 14 C
6 protons
7 neutrons
6 protons
8 neutrons
<0.01%
Carbon = 12.011

Mass number is the number of protons and neutrons in the nucleus of an isotope.
Mass # = p + + n 0
Arsenic
Phosphorus
18
75
8
16
8
33
15
18
75
31