Do Now• Do you remember anything about

atoms?– Make an atom of carbon using Make an atom of carbon using

play-doughplay-dough– Include the #

•protons, •neutrons •and electronselectrons!•WORK AS A TABLE

6

Carbon

Chapter 4Chapter 4

The Chemical Basis of LifeThe Chemical Basis of Life

Lesson ObjectivesLesson Objectives

• Identify the most common Identify the most common elements in living thingselements in living things

• Recognize: Elements Vs Recognize: Elements Vs CompoundsCompounds

• Review the structure of atomsReview the structure of atoms

7 Slides (Wordy.. Take NOTES)

Section 4.1Section 4.1 Life Requires about 25 Life Requires about 25

Chemical ElementsChemical Elements• Everything is made up of matterEverything is made up of matter

• What is matter?

• Regardless of the form of matter, it is Regardless of the form of matter, it is composed of elementscomposed of elements

• What are elements? Your basic “ingredients”Your basic “ingredients”

• About 25 elements are essential to lifeAbout 25 elements are essential to life– Oxygen, Carbon, Hydrogen, Nitrogen Oxygen, Carbon, Hydrogen, Nitrogen

make up 96% of all living matter in your make up 96% of all living matter in your bodybody

– “trace elementstrace elements” = .01% but critical still are Iodine, IronIodine, Iron, Copper, Fluorine, Manganese, and Selenium.

Compounds• More complex types of matter

– 2+ elements that are chemically combined in a fixed ratiofixed ratio• 1:2 or 2:1 or 1:4 (CO2, H20, CH4)1:2 or 2:1 or 1:4 (CO2, H20, CH4)

– QUESTION: if you have 2 carbon dioxide compounds, how many carbons and oxygens do you have?

• 2 Carbons and 4 Oxygens 2(CO2)

• A compounds properties may differ greatly from those of its component elements – Example: page 73

• Table salt (NaCl) Na (metalic) Cl (gas)• Water (H20) H (gas) O (gas)

• Most compounds are more complex with 4+ elements

Section 4.2 Section 4.2 Chemical Properties & Atomic Chemical Properties & Atomic

StructuresStructures• Different elements have different

properties– Different Different phasesphases at different temps at different temps– Reactions with each other Reactions with each other (Sodium and (Sodium and

Water)Water)

– StructuresStructuresHow are an element’s properties related to

its structure?

AtomsAtoms• Each element consists of a single kind of

atom that is different from the atoms of all the other elements… – Carbon element = carbon atoms– Oxygen element = oxygen atoms

• Carbon atom is the smallest possible Carbon atom is the smallest possible ‘piece’ of the element carbon‘piece’ of the element carbon

• But an atom is NOT the smallest component…

Parts of the AtomParts of the Atom• “Subatomic” particles protons, neutrons,

electrons

– Proton: _________ electrical charge (?)– Electron: _________ electrical charge (?)– Neutron: _________ charge

• An elements physical & chemical An elements physical & chemical properties depend on the properties depend on the number and number and arrangementarrangement of its subatomic particles of its subatomic particles

Positive

Negative

Neutral

+

-

Parts of the AtomParts of the Atom• Nucleus contains the ________ and

__________, tightly packed– Electrons (less mass) continually move

around the outside of the nucleus; very fast– Electric attraction b/w protons and Electric attraction b/w protons and

electrons keep the electrons from electrons keep the electrons from ‘flying’ away‘flying’ away. (gravitational pull)

• IMPORTANTIMPORTANT “cloud” of electrons (pg 75) is not really there.. Path of e- is very hard to trace

Protons

Neutrons

Differences in Differences in ElementsElements

• Atomic Number all atoms of a particular element have the same number of protons which is called the atomic number.– Ex: Helium = 2 b/c it has 2 protons

Word Associations!

Write any word you remember from today’s lesson!

Now.. Choose any 5 and explain what you learned about them in today’s lesson

Do Now

If you have 4 water molecules how many hydrogen atoms and oxygen atoms are there

total?

HH

H

H

IsotopesIsotopes• Isotope Same number of protons but

different number of neutrons– Carbon 12 99% stable– Carbon 13 13 neutrons stable– Carbon 1414 neutrons (unstable/radioactive)

• All carbon has 6 protons, if it didn’t it wouldn’t be carbon

• Radioactive isotopes nucleus decays over time, gives off radiation in the form of matter and energy…many uses for them

Energy Energy (NRG)(NRG) Levels Levels• The first or lowest energy level

(closest to the nucleus) can hold 2 electrons (e-)– Second can hold 8 e-– Third can hold 18

• Chemically reactive if the energy level isn’t completely filled

• Inert if the energy levels are filled (stable)

RememberHow tightly electrons are held by the protons

in the nucleusand

The amount of energy they haveAffect how atoms react with one another…

ENERGY LEVELS!!

Energy LevelsEnergy LevelsCarbon Energy Levels

Carbon = 6 electrons

Atomic # = number of protons = # electrons1

2

5

3

4

6

Periodic Table Coloring!

11

HydrogenHydrogen

HH

1 p+

1 n

Green

Atomic Number

YellowYellow

ElectronElectronBlue

1st energy levelRed

Nucleus

Purple

Orange

Atomic

Symbol

Label!!

Nucleus

Chapter Re-Cap Chapter Re-Cap (4.1-4.2)

• What is matter?• What is an element?• What is a compound (fixed ratio?)• What are 3 subatomic particles and

their charges?• What prevents electrons from “flying

away?”• What is an isotope? (Example)• Describe the first 3 energy levels.

4.3 Chemical 4.3 Chemical BondsBonds

• Reactions (rxn)(rxn) between atoms result in filled outer NRG levels– Reactions can be transferring e- or

sharing them between atoms• Creates an attraction (chemical bond) holds

them together

– 2 types of 2 types of Chemical BondsChemical Bonds • ionic ionic • covalent bonds!covalent bonds!

Ionic Bonds!• Occurs when an atom transferstransfers an e-

from another atom• Happens if the outer most layer is not

filled• Atoms “want” to be “complete”…this

happens when their shells are filled– First layer has 2e- , Second has 8e-

•Attraction b/w atoms that are incomplete to try and steal those e- to make itself complete

– Example: NaCl (page 78)

Ionic Bond Example Na LOST Na LOST an e- so an e- so it it became became more more positivepositive

Cl Cl GAINED GAINED an e- so an e- so it it became became more more negativnegativee

Ionic Ionic bondsbonds• When ionic bonds occur the charges of charges of

the original atoms change…the original atoms change…– The atom that loosing the e- now is

positive• Na is now Na+ (because it lost the e- )• Cl is now Cl- (because it gained the e-)

•These are now called ions; – they have become electrically charged

as a result of gaining or loosing an e-

Covalent bonds• Atoms sharing e-sharing e- is a covalent bond• The number of bonds an atom can form

usually equals the number of additional e- that

will fill its highest NRG will fill its highest NRG levellevel– Example (page 79)

• Hydrogen has 1e- (but its shell can hold 2)• Oxygen has 6e- (but its shell can hold 8)

Covalent Bonds Hydrogen 1e- = H (but can hold 2 so will form 1 other bond)

Oxygen 6 e- = O (but can hold 8 so can form 2 other bonds)

Remember that they want to fill their shells!Hydrogen can fill its shell if it takes some from

oxygenBUT oxygen doesn’t want to give one up cause then

it is REALLY unstable… SO they share!! (yay) WATER

H O H

Covalent Bonds

4.3-4.4 mini book

7 pages Due Friday 9/21– Ionic bonds

– Covalent bonds

– Chemical reactions

– Structure of water

– 2 pages for life supporting properties

– Last page pH

Molecules• 2+ atoms held together by

covalent bonds form molecules– Chemical formula

•Number and type of atoms in molecule (H2O)

– Structural formula•How atoms are linked by bonds (H-O-H)

– Space Filling Model•Spheres symbolize

Stop

Chemical Chemical ReactionsReactions

• Molecules can become rearranged into other molecules as bonds break (absorb NRG from environment) or form (release NRG from environment)

– “Chemical reactions” result in the formation of 1 or more new substances

Chemical reactions• Formation of water

Reactants + Products

H O 2(H2O)

*Chemical RXNs neither create nor destroy atoms, but rearrange them!!

Play-dough Chemical Bonds!

Do you remember…Do you remember…• What is the differencedifference between an

ionic bond and a covalent bond?• Na is now Na+… what happenedwhat happened?

What is Na+ now called?

• O can form how many bonds? What is this type of bond called?

• Draw what a carbon atom looks like (label protons, neutrons, nucleus, electrons)– Atomic # = 6

4.4 Unique Properties of Water

• All living things depend on water• Earth’s abundance of water is a major

reason why it supports life (as we know it)

• 2 major parts to water’s properties– Structure– Interactions of its molecules

The Structure of WaterThe Structure of Water

Giant Post Its!!1. Table 1 Structure of water

2. Table 2 Cohesion & Adhesion

3. Table 3 Temperature Moderation

4. Table 4 Low Density of Ice & ability to dissolve other substances

5. Table 5 Acids, Bases and pH, buffers

6. Sum up section 4.4

Future Outlook…

• Due Tomorrow- 4.3 CC

• Due Wednesday- 4.4 P.R. (5)

• TUESDAY 9/22 Chapter 4 Test!

Exit ticketExit ticket

• Fill in where the electrons would be for sodium (Na) – Atomic Number = 11

Na

1

3

2