Atoms!

What is an atom? Please write your answer in a complete

sentence or two.

Atoms are small

• An atom is the smallest piece of matter that is stable under normal conditions.

• All matter is made up of atoms

(almost) Everything is made of atoms!

Sugar

Even You and Every Other Living Thing are Made up of Atoms.

• Matter: anything that has mass and takes up space.

• Keratin is a protein that is made of matter.

• Everything except energy is made up of matter

How small?

1 human is made up of about 100,000,000,000,000 cells!

…and 1 cell is made up of about 100,000,000,000,000 atoms

Atoms are Ridiculously Small

A MILLION atoms in a straight line would be as thick as a single human hair!!!

The radius of a carbon atom is only 0.22 nm

Good thing Science has Powerful Microscopes!

• Each bright spot is a single atom

Elements: substances made up of only 1 type of atoms

• An element is a substance made up of only 1 type of atom.

Only silver atoms in

here!

Compounds

• Compounds are substances made of more than one type of atom, joined together

Water is a compound

made of oxygen and hydrogen

atoms.

Different Elements = Different Atoms

• Atoms of different elements are different from one another because they have different numbers of protons, neutrons, and electrons.

Molecules

• A molecule is the smallest piece of a compound.

Wally the Water Molecule says: “If I get

broken down any farther, I won’t be water anymore… I’d just be a

mixture of hydrogen and oxygen!”

Wally

Parts of an atom: Label the diagram

Atoms contain 2 parts:

The atomic nucleus contains protons and neutrons

Electrons fly around the nucleus near the speed of light

Atom’s radius = 170 pmNucleus’ radius = 0.0027

pm105 = 5 orders of

magnitude.

Fruit Fly length = 0.002 mCamden Yard’s radius =

150 m105 = 5 orders of

magnitude.

Atoms

• Atoms are made of three particles:– Protons

• Positive Charge• In Nucleus

– Neutrons• Neutral Charge• In Nucleus

– Electrons• Negative Charge• Outside of Nucleus in Electron Cloud• Have Negligible (zero) Mass

Wait…Electron Cloud?

Electrons are seemingly everywhere at once!

• We cannot pinpoint electrons to one given spot at one given moment – they move too fast

• They are PROBABLY found in various energy levels around the outside of the nucleus: