Size & Scale of Atoms
Bell Work 12/7/11 – 5 min
1.Substance X has a density of 2.00 kg/cm3.
What would the mass of a 30.0 cm3 sample
be?
2.One kilogram weighs 2.2 lbs. How much
would the sample weigh?
D=M
V
DV = M (2.00)(30.0) = M
60.0 kg = M
60.0 kg x 2.2 lbs =
1
1 kg
132 lbs
Comparing Substance X
• This bronze cube has a density of 8.76 g/cm3*
– The 30.0 cm3 cube weighs 0.63 lb.
• Mercury has a density of 13.5 g/cm3
– 30.0 cm3 would weigh 0.81 lb.
• Osmium (Os) has a density of 22.57 g/cm3
– It’s the densest element.
– 30.0 cm3 would weigh 1.49 lb!
• Substance X has a density of 2,000 g/cm3.
– That’s 2.00 kg/cm3 in g/cm3
– 30.0 cm3 would weigh 132 lbs!!
*more precise
Is Substance X real?
• No known substance has a density of about
2,000 g/cm3 . 
• HOWEVER….
• The nucleus of an atom has a density of
200,000,000,000,000 g/cm3!
– That’s 200 billion kg/cm3.
– That weighs 440 billion lb/cm3
• 30.0 cm3 would weigh 13 trillion lbs!
• The cube of solid
neutrons would
weigh 270,000
Empire State
Buildings!!!!!
– 365 tons
– 730 million lbs
• So dense, it’d tear
through to the
center of Earth!
– (Actually it’ expand.)
Density of Neutron Star
• 2.0 x 1026 kg/km3 (nasa website)
• 4 to 8 times mass of Sun
• these stars finish burning their nuclear fuel,
then…supernova explosion
• The central region of the star collapses under
gravity, so much that protons and electrons
combine to form neutrons.
• Hence the name "neutron star".
Today you are going to…take notes & see an awesome
planetarium presentation about the scale of atoms
So you can develop an appreciation and deeper
understanding of:
– the density of a nucleus
– the relative mass of protons & electrons
– the scale of an atom and its subatomic particles
You’ll know you’ve got it when…you can
• Recite the density of a nucleus
• Compare and contrast the solar system and an atom
What about the mass of an e-?
• About 0.05% the mass of a proton
• mass of proton : mass of electron ::
• mass of Subaru Outback : mass of bottle of water
• 1500 kg (weighs 3300 lbs) : 0.82 (weighs 1.8 lbs)
• Compared to the mass of a p+, the mass of an e- is
negligible!
What about the mass of a no?
• It’s about the same as the mass of a p+.
• Look at solar system overview
Solar System vs. Atom
• If the nucleus of a hydrogen atom were the size
of the sun, how big would its electron be? (wait)
• A little over half the size of Pluto!*
• Diameter of sun
87,000 mi
• Diameter of electron*
850 mi
Size of Solar System
• Let’s look at our solar system! (next screen is black)
•
If the sun were the nucleus of a hydrogen atom, how far away would the e- be?
Solar System vs. Atom
• If the nucleus of a hydrogen atom were the size
of the sun, how far away would its electron be?
• Distance to Mercury
29,000,000 mi
• Distance to Earth
93,000,000 mi
• Distance to Jupiter
483,000,000 mi
• Distance to Pluto
3,700,000,000 mi
• Distance to e- (H atom)
870,000,000,000 mi
• It’d be about 24 times as far as Pluto!
Orbitals!
• s orbital is shaped like a sphere
• How many s orbitals are there in each
level?
Orbitals!
• p orbital is shaped like a dumbell
• How many p orbitals are there in each
level?
Orbitals!
• d orbital is shaped like a double dumbell
• How many d orbitals are there in each
level?
Orbitals!
• f orbital is shaped like a sphere
• How many f orbitals are there in each
level?
Bell Work 12/18 – 5 min
1. Mr. Shuster weighs about 154 lbs. Find his
mass in kilograms. (1 kg weighs 2.2 lbs)
2. If Mr. Shuster were squished to the point that
there were no space in the atoms that
compose his body, what would his volume
be? (same as density of neutron star)
Bell Work 12/8/11 – 5 min
Mr. Shuster weighs about 154 lbs. Find his mass in kilograms.
(1 kg weighs 2.2 lbs)
1. If Mr. Shuster were squished to the point that there were no
space in the atoms that compose his body, what would his
volume be?
154 lbs
1
D=M
V
V=
V=M
D
x
1 kg =
2.2 lbs
77.0 kg
200,000,000,000 billion kg/cm3
= 0.000 000 000 385 cm3
= 3.85 x 10-10 cm3
= 385 µm3
70.0 kg
• 72” x 10” x 18” 
• 22.3 µm x 3.09 µm x 5.57 µm = 385 µm3
• Mr. Shuster would be 22.3 µm tall.
• A dust mite is 400 long, but Mr. Shuster,
being a fierce hunter/ninja/boxer, could
probably still take at least 3 on at once.
More!
• Mr. Shuster would be invisible to the
naked eye!
• You’d miss Mr. Shuster, but don’t
worry…you’d still be able to see him with a
light microscope 
Work for Mr. Shuster’s
dimensions
• 72z x 10z x 18z = 385 µm3
• z = .30970
Post-It Activity
• Draw a 1 mm dot on a post it and put it at
one end of the cafeteria hallway
• Write electron  but don’t put a dot on the
electron. Write “too small to see!” it’s
about 1000 times smaller than the proton I
think.
Atomic Particles
Particle
Charge
Mass (kg)
Location
Electron
-1
9.109 x 10-31
Electron
cloud
Proton
+1
1.673 x 10-27
Nucleus
0
1.675 x 10-27
Nucleus
Neutron
Objectives
• Develop an appreciation and deeper
understanding of:
– the density of a nucleus
– the relative mass of protons & electrons
– the scale of an atom and its subatomic particles
• Recite the density of a nucleus
• Compare and contrast the solar system and an
atom
• Identify the shapes of the s, p, d, and f orbitals
• What happened when you combined alcohol
and water in the lab?
• Why?
Closure
1. Describe an atom. Include the words
nucleus, protons, electrons, neutrons,
space, and dense.
2. Give 3 ways an atom is similar to our
solar system.
3. Give 3 ways an atom differs from our
solar system.
4. What is the density of a nucleus? How
many pounds would 1 cm3 weigh?
What about the mass of an e-?
• About 0.05% the mass of a proton
• mass of proton : mass of electron1.8 lbs
Orbitals
Electrons can be in 4
types of orbitals within
an energy level…
Named s, p, d, or f
Don’t worry about them
for now…we’ll talk more
about them later.