Chemistry of LifeChemistry of Life

AtomsAtomsGreek for “indivisible”Greek for “indivisible”

Smallest possible particle of anSmallest possible particle of an

elementelement

Made up of Made up of Proton (+)Proton (+)Neutron(=)Neutron(=)Electron(-)Electron(-)

Nucleus= central core of atom made Nucleus= central core of atom made up of proton and up of proton and neutronneutron

Surrounded by electronsSurrounded by electrons

2

2

2

Protons

Neutrons

Electrons

Helium atom

ElementsElementsDetermined by the number of protons in Determined by the number of protons in the atomthe atom

All atoms of that element have the same All atoms of that element have the same number of protonsnumber of protons

Atomic number= number of protonsAtomic number= number of protons

Number of electrons and neutrons is not Number of electrons and neutrons is not always consistent.always consistent.

Periodic table is set up to show an Periodic table is set up to show an element based on it’s atomic mass and element based on it’s atomic mass and the number of electrons in it’s outer shell. the number of electrons in it’s outer shell.

IsotopesIsotopes• An Isotope is an element with a An Isotope is an element with a

different number of neutrons than different number of neutrons than protonsprotons

• Ex: Carbon 12, Carbon 13, Carbon 14Ex: Carbon 12, Carbon 13, Carbon 14

• radioactive isotope: an isotope where radioactive isotope: an isotope where the nucleus decays over time giving off the nucleus decays over time giving off radiationradiation

ElectronsElectrons•When an atom is When an atom is left alone the left alone the electrons equal the electrons equal the protonsprotons

•Many atoms will Many atoms will lose or gain one lose or gain one electron in bondingelectron in bonding

•Electrons in the Electrons in the highest energy level highest energy level (valence electrons) (valence electrons) determine how it determine how it will interact with will interact with other atoms. other atoms.

ElectronsElectronsElectron

Outermost electron shell (can hold 8 electrons)

First electron shell (can hold 2 electrons)

Hydrogen (H)Atomic number = 1

Carbon (C)Atomic number = 6

Ionic BondsIonic BondsA bond that occurs A bond that occurs when an atom when an atom transfers an electron transfers an electron to another atom.to another atom.

EX: NA-EX: NA- CL CL

Sodium gives an Sodium gives an electron to electron to chlorinechlorine

NA+ & Cl-NA+ & Cl-

NaClNaCl

This leads to IonsThis leads to Ions

Ion= an atom that Ion= an atom that has become has become electrically charged electrically charged (+ or-)(+ or-)

Covalent BondCovalent BondA bond that forms A bond that forms when two atoms when two atoms share electrons. share electrons.

The number of bonds The number of bonds that can be formed is that can be formed is determined by the determined by the number of electrons number of electrons needed to fill the needed to fill the highest outer levelhighest outer level

MoleculesMoleculesA molecule is two or more A molecule is two or more atoms held together by a atoms held together by a covalent bond. covalent bond.

Chemical Chemical ReactionReaction

The breaking of old and The breaking of old and forming of new bonds to forming of new bonds to make new chemical make new chemical substances. substances.

Reactant: The starting Reactant: The starting materialsmaterials

Product: The ending materialsProduct: The ending materialsReactants Product

Water propertiesWater properties

WaterWaterAll living things are dependent on All living things are dependent on waterwater

Cells are 70% to 95% waterCells are 70% to 95% water

Water is the only compound found on Water is the only compound found on earth in all 3 formsearth in all 3 forms

Water is one oxygen covalently Water is one oxygen covalently bonded to two hydrogen's. bonded to two hydrogen's.

Although this is a covalent bond the Although this is a covalent bond the oxygen pulls the shared electrons oxygen pulls the shared electrons closer to itself making it more closer to itself making it more negative and making the hydrogen negative and making the hydrogen more positive. more positive.

Water propertiesWater propertiesOxygen has 6 electrons in it’s highest shell. It wants to Oxygen has 6 electrons in it’s highest shell. It wants to have 8have 8

Hydrogen has only one electron in it’s outer shell, it Hydrogen has only one electron in it’s outer shell, it wants 2.wants 2.

They share their electrons allowing for oxygen to gain They share their electrons allowing for oxygen to gain 2 to make 8 and hydrogen each gets one making it 2. 2 to make 8 and hydrogen each gets one making it 2.

Oxygen has 8 protons in it’s nucleus and this then Oxygen has 8 protons in it’s nucleus and this then makes it pull the electrons closer to make the atom makes it pull the electrons closer to make the atom neutral. neutral.

This pull is why water is considered polar and slightly This pull is why water is considered polar and slightly misshapen. misshapen.

The slight polarization of water leads to hydrogen The slight polarization of water leads to hydrogen bonds where they are attracted due to polarization not bonds where they are attracted due to polarization not electron sharing or trading. electron sharing or trading.

Water structureWater structure

Waters life-supporting Waters life-supporting propertiesproperties

Cohesion: The Cohesion: The tendency of tendency of molecules of the molecules of the same kind to stick same kind to stick to one another. to one another.

Important in Important in plants because as plants because as water evaporates water evaporates it pulls itself it pulls itself upward in plants. upward in plants.

Adhesion: Adhesion: Attraction that Attraction that occurs between occurs between unlike molecules.unlike molecules.

Important because Important because water sticks to the water sticks to the sides of the plant sides of the plant tubes and helps tubes and helps combat gravity. combat gravity.

Waters life-Waters life-supporting supporting propertiesproperties

Temperature moderation: Water has Temperature moderation: Water has a very strong ability to resist change a very strong ability to resist change in temperature due to hydrogen in temperature due to hydrogen bonding between moleculesbonding between molecules

Water allows for temperature Water allows for temperature regulation of the world by staying regulation of the world by staying cool in the summer and warm in the cool in the summer and warm in the winterwinter

Waters life-supporting Waters life-supporting propertiesproperties

Ice: the solid form of Ice: the solid form of water that is lower water that is lower density than the liquid density than the liquid form. As water freezes form. As water freezes the molecules move the molecules move further apart. further apart.

Important because it Important because it allows animals to allows animals to continue to live under continue to live under frozen water instead of frozen water instead of being frozen from the being frozen from the bottom up. bottom up.

Waters life-supporting Waters life-supporting propertiesproperties

Water has a great ability to Water has a great ability to dissolve other substances.dissolve other substances.

Water is the universal solventWater is the universal solvent

Solvent: The substance that Solvent: The substance that dissolves another substancedissolves another substance

Solute: The substance that is Solute: The substance that is being dissolvedbeing dissolved

Solution: A uniform mixture of Solution: A uniform mixture of two or more substances. two or more substances.

Acids, Bases, Acids, Bases, Buffers, PhBuffers, Ph

Ph ScalePh ScaleWater sometimes breaks into ion’s of Water sometimes breaks into ion’s of H+ and OH- H+ and OH-

Hydrogen ion(+) and Hydroxide ion(-)Hydrogen ion(+) and Hydroxide ion(-)

These ions are what determine whether These ions are what determine whether something is an acid or base.something is an acid or base.

The Ph scale is an exponential scale The Ph scale is an exponential scale showing acids and bases. (power of 10)showing acids and bases. (power of 10)

Ph Scale

Scale from 0 to Scale from 0 to 1414

each step is 10x each step is 10x more than the more than the nextnext

0-6 is Acidic0-6 is Acidic

7-8 is neutral7-8 is neutral

8-14 is Basic8-14 is Basic

LE 2-15

Acidic solution

OH

H

HH

HOH

H H

H

OH

OH

OH

OH

OH

H

H

H

H

HH

I ncr

ea

sin

gl y

AC

IDI C

(Hi g

he

r c

on

c en

tra

t io

n o

f H

)Neutral solution

OH

OH

OH

OH

OH

OH

H

H

Basic solution

NEUTRALH

pH scale

Lemon juice, gastric juice

Grapefruit juice, soft drink

Tomato juice

Human urine

Pure water

Human blood

Seawater

Milk of magnesia

Household ammonia

Household bleach

Oven cleaner

Incr

ea

sin

gl y

BA

SIC

(Lo

we

r c

on

cen

tra t

i on

of

H )

OH

OH

OH

OH

OH

OH

H

H

Basic solution

Milk of magnesia

Household ammonia

Household bleach

Oven cleaner

Incr

ea

sin

gl y

BA

SIC

(Lo

we

r c

on

cen

tra t

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of

H )

AcidsAcidsAn acid is any substance An acid is any substance that gives off H+ to the that gives off H+ to the solutionsolution

Ex: lemon juice, stomach Ex: lemon juice, stomach acidacid

Acidic solution

OH

H

HH

HOH

H H

H H

I ncr

ea

sin

gl y

AC

IDI C

(Hi g

he

r c

on

c en

tra

t io

n o

f H

)

pH scale

BasesBasesA base is a compound that A base is a compound that removes H+ from the removes H+ from the solution by giving off OH- solution by giving off OH- to bond with the H+to bond with the H+

Ex: Soap, Bleach, Oven Ex: Soap, Bleach, Oven cleanercleaner

OH

OH

OH

OH

OH

OH

H

H

Basic solution

Milk of magnesia

Household ammonia

Household bleach

Oven cleaner

Incr

ea

sin

gl y

BA

SI C

(Lo

we

r c

on

cen

tra t

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of

H )

BufferBufferCells are very sensitive to H+ and Cells are very sensitive to H+ and OH- ions. Even a slight change in OH- ions. Even a slight change in Ph will affect a cell. Ph will affect a cell.

A buffer will accept H+ ions when A buffer will accept H+ ions when they are too high and will donate they are too high and will donate H+ when they are too low. H+ when they are too low.

Blood is a great example of a Blood is a great example of a bufferbuffer

OH

OH

OH

OH

OH

H H

H

HH

Neutral solution

NEUTRALH

Tomato juice

Human urine

Pure water

Human blood

Seawater