Friday, 10/27

• Compounds and Elements

• Atomic, molecular, and network matter

• Chemical formulas• Molecular families and

bonding geometries• Instrumentation

Friday, 10/27

• Compounds and Elements

• Atomic, molecular, and network matter

• Chemical formulas• Molecular families and

bonding geometries• Instrumentation (?)

• The wave model tells us what atoms are like

• We can understand how atoms bond

• These bonds are a major part of our daily experience.

• Our lives are governed largely by chemistry

Why we’re doing this

Our approach

• 10/27 Atoms molecules and networks

• 10/30 Reactivity• 11/1 Bonding in metals

and semiconductors• 11/3 Ionic bonds• 11/6 Covalent bonds• 11/8 Some applications

• The wave model tells us what atoms are like

• We can understand how atoms bond

• These bonds are a major part of our daily experience.

• Our lives are governed largely by chemistry

Why we’re doing this

(Participation question)Which of these is a compound?

Hydrogen

Neon Nitrogen

Water

25% 25%25%25%1. Hydrogen

2. Neon

3. Nitrogen

4. Water

Compounds: matter that contains two or more atoms in a fixed, definite proportion.

Sulfuric acid, hydrogen peroxide, salt, sugar, bleach, sodium bicarbonate, etc.

(Participation Question)What is the difference between a pure substance

and an element?

They are the same thing Pure substances hav... Elements have a defi...

33% 33%33%1. They are the same

thing2. Pure substances have a

defined, unchanging chemical composition, but elements are just one kind of atom.

3. Elements have a defined, unchanging chemical composition, but pure substances are just one kind of atom.

Chemical Matter

Chemical Matter

• Atomic Matter: The noble gases

• Simple atoms in solid, gas, and liquid state

“I told you they’s organized”

Molecular matter

• Definite molecules in solid, liquid, and gaseous states

• Atomic Matter: The noble gases

• Simple atoms in solid, gas, and liquid state

“I told you they’s organized”

Molecular matter

• Definite molecules in solid, liquid, and gaseous states

• Extended bonding, no distinct molecles.

• Metals, salt, quartz, etc.

Network matter

Can you tell how bonding influences melting and boiling temperatures?

atomic

molecular

network

molecular

(Participation question)How many hydrogen atoms:

H2O

1 2 3 4 5

20% 20% 20%20%20%1. 1

2. 2

3. 3

4. 4

5. 5

(Participation question)How many hydrogen atoms:

2C2H4

2 4 6 8 10

20% 20% 20%20%20%1. 2

2. 4

3. 6

4. 8

5. 10

The family of simple hydrocarbons

http://ps100.byu.edu/molecule_sg/simple_hydrocarbons.html

Molecular Orbitals

• Electrons in molecules have NEW standing wave descriptions

• Sometimes we talk about shared pairs of electrons

Molecular Orbitals

• Electrons in molecules have NEW standing wave descriptions

• Sometimes we talk about shared pairs of electrons

Molecules vibrate

Infrared Absorption

• Molecular vibration can be caused by photon absorption

Molecules vibrate

Infrared Absorption

• Molecular vibration can be caused by photon absorption

Molecules break

Mass Spectroscopy

• Measure molecular fragments to determine the original molecule

Molecules break

Mass Spectroscopy

• Measure molecular fragments to determine the original molecule

• Some molecules can be formed into crystals

• Crystal form and content determined by x-ray scattering

Molecules crystallize