Making Models of Atoms and Molecules

1) Has anyone ever really SEEN an atom?Not with the naked eye, of course!

Fancy machines like this scanning tunneling microscope allow us to see evidence of their existence.

How do we know they exist?

2) Why are models helpful?

They help us visualize things we can’t see.

Some models show us very small things (like atoms) up close while other models help us see very

BIG things (like the solar system) all at one time.

3) How many different subatomic particles does an atom have?

Three: proton (+) neutron (0) electron (-)

4) Where are these subatomic particles located in the atom?

proton - in the nucleusneutron - in the nucleus next to the protonselectron - speeding around in the electron cloud

5) Which of the subatomic particles (if any) move about?

The electrons!

6) How can we use the periodic table to determine the number of protons in an atom?

• The number of protons = the atomic number.

• Every different type of atom (element) has a different atomic number.

• You can think of this as its personal ID number.

7) How can we use the periodic table to determine the number of electrons in an atom?

Number of electrons = number of protons

8) How can we use the periodic table to determine the number of neutrons in an atom?

Atomic mass – number of protons = number of neutrons

95.94 ~ 96 (round off)

96-42 = 54 neutrons

Let’s begin!

• Protons – yellow peas

• Neutrons – brown peas

• Electrons – sprinkles

Fill out your card and get it checked before you glue any parts.

Name & Symbol of atom: _______________________________ ______

Atomic number: _________ Atomic mass (rounded off): ________

# of protons: __________ # of neutrons: ___________

# of electrons: __________ # of valence electrons: _________

Electron Configuration: ________________________________________

Student Name: ______________________________________________

What will our atoms look like?

What will our molecules look like?

We will be counting the atoms and the different elements in each molecule. The next slide will show you how to add the information to each box.

Name of molecule: _____________________

Formula: _____________________________

# of Atoms=____# of Elements=____Compound? Yes or No? (See the next slide)

We will be counting the atoms and the different elements in each molecule. Add this info to each card as shown in red below.

Name of molecule: _____________________

Formula: _____________________________

A=____E=____C- _______

waterH2O

carbon dioxideCO2

oxygenO2

O O

ethanolC2H6O

nitrogenN2

nitric acidHNO3

ozone

O3 O

O

O

chlorine dioxideClO2

hydrogen peroxideH2O2

ammoniaNH3

hydrogenH2

fluorine

F2 FF

methaneCH4

nitroglycerinC3H5N3O9

Can you pick out the atoms?

oil of spearmintC10H14O

Can you pick out the atoms?

glucoseC6H12O6

sucroseC12H22O11

Each white sphere represents a hydrogen atom (black = carbon, red = oxygen)

The following are ionic compounds and they are not considered molecules (which have covalent bonds.)

magnesium fluoride

MgF2

baking sodaNaHCO3

potassium nitrate

KNO3

K

N

O

O

O

potassium chloride

KCl

rustFe2O3

yields

saltNaCl

sodium hydroxideNaOH