The Structure of the Atom
The Building Block of Matter
Atomic Structure
At the conclusion of our time
together, you should be able to:
 List the 3 major subatomic
particles with their relative
size, mass and charges
 List 3 other sub-subatomic
particles (not General)
 Define the mass number,
atomic number and symbol
from an element on the
periodic table
Warning:
Old Farts
Swimming!!!
The Atom
An atom consists of a
 nucleus
 (of protons and neutrons)
 electrons in space about the nucleus.
Electron cloud
Nucleus
Atoms are the smallest particles of an
element that retains the chemical properties
of that element

Parts:
 Nucleus – small region in
the center of the atom.
(+ charged protons, and o
charged neutrons)
 Electron Cloud – large
region, compared to
nucleus, where electrons
are found.

Check out the Size of Nucleus vs.
Electron Cloud
• If Cleveland Stadium were an atom, a marble
on the 50 yard line would represent the nucleus.
• The atom is extremely small. One teaspoon of
water has 3 times as many atoms as the Atlantic
Ocean has teaspoons of water.
Can We See Atoms?
Magnesium atoms
(white) above
Boron atoms (grey)
seen by the
transmission
electron microscope
Questions about teenage men
answered by teenage women!!!
Q: What do you call an
intelligent, good looking,
sensitive young man?
A: A rumour
Proton
Neutron
Electron
Electron shell / Electron cloud
Nucleus
The Atom
Nucleus
The center of the atom.
(it has protons & neutrons)
Electron shell / Electron cloud
The Atom
Summary of Atomic Particles

Protons (p+)




+ electrical charge
mass = 1.673 x 10-24 g
relative mass = 1.007 atomic mass units (amu)
but we can round to 1
Neutrons (no)



no electrical charge
mass = 1.675 x 10-24 g
relative mass = 1.009 amu but we can round to 1
Summary of Atomic Particles

Electrons (e-)



negative electrical charge
mass = 9.109 x 10-28 g
relative mass = 0.0005 amu
but we can round to 0
Proton
Mass
Charge
Neutron Electron
1 amu
1 amu
0 amu
+1
0
-1
Questions about teenage men
answered by teenage women!!!
Q: Why do young men whistle
when they are sitting on the
toilet?
A: It helps them remember
which end to wipe!
Tevatron –
•World’s highest energy
particle accelerator.
•4 miles in circumference
•Why? To find even smaller
particles!!!
We send protons and antiprotons in
opposite directions, and smash
them together.
Particle
accelerator
Particles
Matter
anti-Matter
Example:
electron
e-1
positron
e+1
Particles
Matter
anti-Matter
Example:
Proton
+1
P
anti-Proton
-1
P
Quarks
Up
2
3
Leptons
electron
e-1
Down
-1
3
Neutron
d
Made of
3 Quarks
u
1 up
2 down
d
Proton
u
Made of
3 Quarks
2 up
1 down
d
u
Interesting Name for a Boat!!
Mass Comparison
Proton is about
1800 x electron
-1
e
Proton
.
Electron
Subatomic Particles Summary

Quarks

Fast moving point
of energy
• Sum of the charges is
the electrical charge
 Up quark = + 2/3
 Down quark = - 1/3
He
Quark Calculations
(for protons and neutrons)

Each proton is 2 up quarks and 1 down
quark
 2(2/3)
+ 1(-1/3) = 4/3 – 1/3 = 3/3 or +1
• Each neutron is 2 down quarks and 1 up
quark
2(-1/3) + 2/3 = 0
Great
Little
Invention
!!!!
Atomic Number, Z
All atoms of the same element have the
same number of protons in the nucleus, Z
13
Al
26.981
Atomic Number
Atomic Symbol
AVERAGE Atomic Mass
Mass Number





Number of protons + number of neutrons in an
atom.
Example: 2 protons and 2 neutrons
When solving for number of neutrons:
round average atomic number properly,
subtract the atomic number from the mass
number.
Example: K with atomic number 19 and average
atomic mass 39.0983 amu.
20 neutrons
Mass Number, A


C atom with 6 protons and 6 neutrons is
the mass standard
= 12 atomic mass units (amu)

Mass Number (A)
= # protons + # neutrons

NOT on the periodic table

It is the Average atomic mass (which is
on the periodic table) rounded to the
nearest whole number
Element Symbols


Hyphen Notation:
Element symbol – Mass # (rounded)
Example: Helium  He-4
Nuclear Symbol:
Superscript Mass Number,
Subscript Atomic Number,
Symbol
4
Example:
2 He
Atomic Structure
Let’s see if you can:
 List the 3 major subatomic
particles with their relative
size, mass and charges
 List 3 other sub-subatomic
particles
 Define the mass number,
atomic number and symbol
from an element on the
periodic table
In Summary


Atomic number =
the # protons and also the # electrons if
the atom is neutral
• Mass Number from PT =
•Average atomic number rounded to the
nearest whole number
• Mass Number =
•# protons + # neutrons
WHY GOD MADE MOMS
Answers given by 2nd grade school children
to the following questions:
Why did your mom marry your dad?
1. My dad makes the best
spaghetti in the world, and my
mom eats a lot
2. She got too old to do anything
else with him.
3. My grandma says that mom
didn't have her thinking cap on.
Get Your
Clicker!!!
Which two subatomic particles are found in
the nucleus of an atom?
1.
2.
3.
4.
5.
Proton / Electron
Proton / Neutron
Electron / Neutron
Proton / Quark
Neutron / Quark
The atomic number represents the number
of … if neutral.
1.
2.
3.
4.
Protons
Neutrons
Protons + Neutrons
Protons + Electrons
The mass number represents the number of
…
1.
2.
3.
4.
Electrons
Protons + Electrons
Protons + Neutrons
Neutrons + Electrons
What is the correct Hyphen Notation for
Calcium
1.
2.
3.
4.
5.
Ca – 20
Ca – 40.078
Ca – 40.08
Ca – 40.1
Ca - 40
An atom has 14 protons and 20 neutrons.
The element is …
1.
2.
3.
4.
Si
Ca
Se
C
An atom has 15 protons and 17 neutrons.
What element is it?
1.
2.
3.
4.
Cl
He
Ge
P
The isotope C-16 has which of the
following?
1.
2.
3.
4.
5.
6.
16 protons
6 neutrons
8 neutrons
10 neutrons
12 electrons
16 neutrons
The isotope N-16 has which of the
following?
1.
2.
3.
4.
5.
6.
16 protons
7 neutrons
8 neutrons
9 neutrons
16 electrons
16 neutrons
The nucleus contains (select the best
answer)…
1.
2.
3.
4.
5.
6.
7.
Protons
Neutrons
Electrons
Photons
Answer 1 and 2
Answer 1 and 3
Answer 2 and 3
If an element with atomic #12 has 13
neutrons, what is it’s atomic mass?





1.
2.
3.
4.
5.
12
13
24
25
not listed
If an element with atomic #12 has 13
neutrons, how many electrons does it have?





1.
2.
3.
4.
5.
12
13
24
25
not listed
If an atom is neutral, which subatomic
particles would be equal?
1.
2.
3.
Protons and neutrons
Neutrons and
electrons
Protons and
Electrons
If an element with atomic #30 has a mass
#65, how many neutrons will it contain?





1.
2.
3.
4.
5.
30
65
95
35
not listed
WHY GOD MADE MOMS
Answers given by 2nd grade school children
to the following questions:
What's the difference between moms and
dads?
1. Moms work at work and work at home and
dads just go to work at work.
2. Moms know how to talk to teachers without
scaring them.
3. Dads are taller and stronger, but moms have all
the real power 'cause that's who you got to ask if you
want to sleep over at your friends.
4. Moms have magic, they make you feel better
without medicine!