Size & Scale of AtomsSize & Scale of Atoms

Bell Work 12/7/11 – 5 min1.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

• 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

Solar System vs. Atom

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 min1. 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 minMr. 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?

D = M V

154 lbs x 1 kg = 1 2.2 lbs

70.0 kg

V = M D

V = 77.0 kg 200,000,000,000 billion kg/cm3

= 0.000 000 000 385 cm3

= 3.85 x 10-10 cm3 = 385 µm3

• 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 ParticlesAtomic ParticlesParticle Charge Mass (kg) Location

Electron

-1 9.109 x 10-31 Electron cloud

Proton +1 1.673 x 10-27 Nucleus

Neutron

0 1.675 x 10-27 Nucleus

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

OrbitalsOrbitalsElectrons 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.