MR. CANOVA’SMR. CANOVA’SScience, Technology, & SocietyScience, Technology, & Society

CLASS CLASS

CHEMISTRY REVIEW:CHEMISTRY REVIEW:HISTORY OF THE ATOMIC MODELHISTORY OF THE ATOMIC MODEL

SUBATOMIC PARTICLESSUBATOMIC PARTICLES

IONIC AND MOLECULAR COMPOUNDSIONIC AND MOLECULAR COMPOUNDS

NAMING AND WRITING FORMULASNAMING AND WRITING FORMULAS

ACIDSACIDS

HISTORY OF THE HISTORY OF THE ATOMIC MODELATOMIC MODEL

SCIENTIST MODELDemocritus: The Greek Model

(460 BC-370 BC)

•Matter can’t be divided forever; there must be a smallest piece (atomos)

•Atoms are indestructible, indivisible, & the fundamental units of matter

Atom: smallest particle of an element that retains the properties of that element.

- no electric charge, electrically neutral

•No experiments to test his theories

SCIENTIST MODEL

John Dalton: Dalton’s Model (1766-1844)

Dalton’s Atomic Theory: All elements are composed of atoms that are

submicroscopic indivisible particles.

Atoms of the same elements are identical & atoms of different elements are different.

Atoms of different elements can physically mix together or chemically combine w/one another to form simple or whole-number ratios to form compounds.

Chemical reactions occur when atoms are separated, rearranged or joined. Atoms of one element can never be changed into atoms of another element.

SCIENTISTSCIENTIST MODELMODEL

J.J. Thomson:J.J. Thomson: Thomson’s Model (1856-Thomson’s Model (1856-1940)1940)

• Used cathode ray tube to discover electronsUsed cathode ray tube to discover electrons• Cathode ray:Cathode ray: glowing beam which travels from glowing beam which travels from

the cathode(-) to the anode(+).the cathode(-) to the anode(+).

- are composed of electrons- are composed of electrons

- are attracted to positive metal plate- are attracted to positive metal plate• Atoms had negatively charged particlesAtoms had negatively charged particles• ELECTRONELECTRON: : negatively charged subatomic particlenegatively charged subatomic particle

• ““Plum Pudding” Model Plum Pudding” Model • (chocolate chip cookie) (watermelon with seeds)(chocolate chip cookie) (watermelon with seeds)

-a ball of positive charge containing electrons -a ball of positive charge containing electrons

Thomson’s ModelThomson’s Model

ELECTRONSEMBEDDED WITHIN

POSITIVE CHARGE

Cathode Ray Tube: Cathode Ray Tube:

Robert Millikan Robert Millikan Oil Drop Experiment (1916)Oil Drop Experiment (1916)

Determined the Determined the charge and mass charge and mass of an electronof an electron

The mass is The mass is 1/1840 of the 1/1840 of the mass of a mass of a hydrogen atom hydrogen atom (less than 1 amu)(less than 1 amu)

SCIENTISTSCIENTIST MODELMODELE. Rutherford:E. Rutherford: Rutherford’s ModelRutherford’s Model

• Gold Foil ExperimentGold Foil Experiment• Discovered that most of atom’s mass is located Discovered that most of atom’s mass is located

in the positively charged nucleusin the positively charged nucleus

NUCLEUSNUCLEUS:: center of the atom composed of center of the atom composed of PROTONSPROTONS & & NEUTRONSNEUTRONS

is 99.9% of the atom’s massis 99.9% of the atom’s mass a marble in a football stadiuma marble in a football stadiumwww.shsu.edu/%Echm_tgc/sounds/ruther.movwww.shsu.edu/%Echm_tgc/sounds/ruther.mov

Empty Space

++++++ + Nucleus

Gold Foil ExperimentGold Foil Experiment: : RutherfordRutherford

PROTONPROTON: : positively charged subatomic particlepositively charged subatomic particle

discovered by Eugen Goldstein (1850-1930)discovered by Eugen Goldstein (1850-1930) put holes in cathode and saw rays traveling put holes in cathode and saw rays traveling

in the opposite direction (canal rays)in the opposite direction (canal rays)

NEUTRONNEUTRON:: subatomic subatomic particle with no chargeparticle with no charge

discovered by Sir James Chadwick discovered by Sir James Chadwick (1891-1974)(1891-1974)

mass is nearly equal to proton (1 amu)mass is nearly equal to proton (1 amu)

Thomson & Rutherford proved Thomson & Rutherford proved

Dalton’s Theory incorrect: Dalton’s Theory incorrect:

ATOMS ARE DIVISIBLEATOMS ARE DIVISIBLE

http://www.mhhe.com/physsci/chemistry/essentialchemistry/flash/ruther14.swfhttp://www.mhhe.com/physsci/chemistry/essentialchemistry/flash/ruther14.swf

SCIENTISTSCIENTIST MODELMODEL

Niels Bohr:Niels Bohr: The Bohr Model The Bohr Model (1885-1962)(1885-1962)

Electrons move in definite orbits around Electrons move in definite orbits around the nucleus (planets around the sun)the nucleus (planets around the sun)

PLANETARY MODELPLANETARY MODEL Electrons are a part of Electrons are a part of energy levelsenergy levels

located certain distances from the located certain distances from the nucleusnucleus

Electrons

++++++ Energy

Levels

Energy LevelsEnergy Levels: region around the nucleus where the: region around the nucleus where the

electron is likely to be moving.electron is likely to be moving. a ladder that isn’t equally spaced a ladder that isn’t equally spaced further the distance, closer the spacingfurther the distance, closer the spacing the higher the energy level the farther it is from the the higher the energy level the farther it is from the

nucleusnucleus

Electrons can jump from 1 energy level to another.Electrons can jump from 1 energy level to another.

Quantum EnergyQuantum Energy: amount required to move an : amount required to move an

electron from its present energy electron from its present energy

level to the next higher one.level to the next higher one.

SCIENTISTSCIENTIST MODELMODELErwin SchrodingerErwin Schrodinger Quantum Mechanic ModelQuantum Mechanic Model

(1887-1961)(1887-1961)• Wave mechanics-mathematicalWave mechanics-mathematical• Probable location of electronProbable location of electron• Cloud ShapedCloud Shaped• Propeller bladePropeller blade

Subatomic particles: Electrons, Protons, & NeutronsSubatomic particles: Electrons, Protons, & Neutrons Atomic NumberAtomic Number: Number of Protons in the nucleus: Number of Protons in the nucleus Whole number written above chemical symbolWhole number written above chemical symbol ExEx: : Hydrogen=1(P)Hydrogen=1(P) Oxygen=8(P)Oxygen=8(P)

SUBATOMICSUBATOMICPARTICLESPARTICLES

Subatomic particles: Subatomic particles: Electrons, Protons, & NeutronsElectrons, Protons, & Neutrons

Atomic NumberAtomic Number: Number of Protons in the : Number of Protons in the nucleusnucleus

• Whole number written above chemical symbolWhole number written above chemical symbolExEx: : Hydrogen=1(P)Hydrogen=1(P) Oxygen=8(P)Oxygen=8(P)

Mass NumberMass Number: Sum of Protons : Sum of Protons ++ Neutrons NeutronsExEx: : Carbon Mass #12 = 6(P) + 6(N)Carbon Mass #12 = 6(P) + 6(N)

Oxygen Mass #16 = 8(P) + 8(N)Oxygen Mass #16 = 8(P) + 8(N)Mass # (#P Mass # (#P + + #N)#N) - - Atomic # (#P)Atomic # (#P) = = #Neutrons#Neutrons

LETS HAVE SOME PRACTICELETS HAVE SOME PRACTICE

6

CCarbon

12

Atomic Number (P)

Mass Number(P+N)

Element Symbol

Element Name

126

Mass Number(P+N)

Atomic Number(P)

C

WHAT GIVES AN ATOM ITS WHAT GIVES AN ATOM ITS IDENTITY?IDENTITY?

IsotopeIsotope: Same # of Protons, : Same # of Protons,

different # of Neutronsdifferent # of Neutrons• Different Mass NumberDifferent Mass Number• Same Atomic NumberSame Atomic Number• Chemically alikeChemically alike

ExEx: : Carbon-12 Mass #12 = 6(P) + 6(N)Carbon-12 Mass #12 = 6(P) + 6(N)

Carbon-13 Mass #13 = 6(P) + 7(N)Carbon-13 Mass #13 = 6(P) + 7(N)

Atomic Mass for isotopes of Carbon = 12.01 amuAtomic Mass for isotopes of Carbon = 12.01 amu

SO, WHAT GIVES AN ATOM ITS SO, WHAT GIVES AN ATOM ITS IDENTITY?IDENTITY?

# of protons gives the atom its identity# of protons gives the atom its identity

# of electrons determines the chemistry # of electrons determines the chemistry of the atomof the atom

# of neutrons only changes the mass of # of neutrons only changes the mass of the atomthe atom

HOW TO DETERMINE HOW TO DETERMINE ELECTRON CONFIGURATIONSELECTRON CONFIGURATIONS

How electrons are arranged around the How electrons are arranged around the nuclei of atomsnuclei of atoms

3 RULES: 3 RULES: Aufbau’s Aufbau’s

• ElectronElectrons enter lowest energy level firsts enter lowest energy level first Pauli Exclusion PrinciplePauli Exclusion Principle

• Orbitals can hold 2 electrons of oOrbitals can hold 2 electrons of opposite spinpposite spin Hund’sHund’s

• Electrons enter oElectrons enter one orbital until parallel spinsne orbital until parallel spins

Orbitals and Electron Capacity of the First Four Principle Orbitals and Electron Capacity of the First Four Principle Energy LevelsEnergy Levels

Principle Principle energy energy

level (n)level (n)

Type of Type of sublevelsublevel

# of # of orbitals orbitals per typeper type

# of # of orbitals orbitals per levelper level(n(n22))

MaximumMaximum# of # of

electrons electrons (2n(2n22))

11 ss 11 11 22

22ss 11

44 88pp 33

33

ss 11

99 1818pp 33

dd 55

44

ss 11

1616 3232pp 33

dd 55

ff 77

USING THE PERIODIC TABLEUSING THE PERIODIC TABLEColumn #Column # NAMENAME Valence Valence

electronselectronsIon ChargeIon Charge

11 Alkali MetalsAlkali Metals Lose 1Lose 1 +1+1

22 Alkaline Alkaline MetalsMetals

Lose 2Lose 2 +2+2

3 to 123 to 12 Transition Transition MetalsMetals

LoseLose VARIESVARIES

1313 Boron groupBoron group Lose 3Lose 3 +3+3

1414 Carbon groupCarbon group Lose/Gain 4Lose/Gain 4 +/- 4+/- 4

1515 Nitrogen Nitrogen GroupGroup

Gain 3Gain 3 -3-3

1616 Oxygen GroupOxygen Group Gain 2Gain 2 -2-2

1717 HalogensHalogens Gain 1Gain 1 -1-1

1818 Inert or Noble Inert or Noble GasesGases

StableStable 00

IONIC AND IONIC AND MOLECULAR MOLECULAR COMPOUNDSCOMPOUNDS

MOLECULAR VS. IONIC MOLECULAR VS. IONIC COMPOUNDSCOMPOUNDS

MOLECULAR COMPOUNDS:MOLECULAR COMPOUNDS:1. Low melting & boiling points1. Low melting & boiling points2. Solids, Liquids, and Gases at room temp.2. Solids, Liquids, and Gases at room temp.3. Sharing of valence electrons3. Sharing of valence electrons4. Two or more 4. Two or more Nonmetallic elementsNonmetallic elements5.5. Contain covalent bondsContain covalent bonds

EX:EX:

HH22OO COCO22 CHCH44

MOLECULAR VS. IONIC MOLECULAR VS. IONIC COMPOUNDSCOMPOUNDS

IONIC COMPOUNDS:IONIC COMPOUNDS:1. High melting & boiling points1. High melting & boiling points2. Composed of ions (cation and anion)2. Composed of ions (cation and anion)3. Electrically neutral3. Electrically neutral4. Crystalline solids at room temperature4. Crystalline solids at room temperature

-coordination #, 3D patterns-coordination #, 3D patterns5. Composed of a 5. Composed of a MetalMetal and and NonmetalNonmetal6. Contains Electrostatic Bonds6. Contains Electrostatic Bonds

EX:EX:

NaClNaCl MgClMgCl22

How to Write an Ionic Formula:How to Write an Ionic Formula:

1. Write down symbols1. Write down symbols

2. Determine Ionic Charges2. Determine Ionic Charges

3. Charges must cancel each other out 3. Charges must cancel each other out

(equal zero)(equal zero)

if not, use criss-cross method to form if not, use criss-cross method to form subscripts to cancel out chargessubscripts to cancel out charges

EXAMPLES:EXAMPLES:Potassium BromidePotassium Bromide KK+1+1 Br Br-1 -1 charges cancel charges cancel KBrKBr

Magnesium OxideMagnesium Oxide MgMg+2 +2 O O-2-2 charges cancelcharges cancel MgOMgO

Aluminum NitrideAluminum Nitride AlAl+3+3 N N-3-3 charges cancel charges cancel AlNAlN

Magnesium ChlorideMagnesium Chloride MgMg+2+2 Cl Cl-1-1 charges don’t cancel, charges don’t cancel, criss-cross criss-cross MgClMgCl22Sodium SulfideSodium Sulfide NaNa+1+1 S S-2-2 charges don’t cancel, charges don’t cancel, criss-crosscriss-cross NaNa22SSAluminum Oxide Aluminum Oxide AlAl+3+3 O O-2-2 charges don’t cancel, charges don’t cancel, criss-crosscriss-cross AlAl22OO33

Naming an Ionic Formula:Naming an Ionic Formula:1. Write the name for the metal and nonmetal1. Write the name for the metal and nonmetal

2. Check to see if the metal has more than 2. Check to see if the metal has more than

one charge (Cu, Fe, transition metals)one charge (Cu, Fe, transition metals)

3. If metal has more than one charge, you 3. If metal has more than one charge, you

must do a “reverse” criss-cross to must do a “reverse” criss-cross to

determine formuladetermine formula A Roman Numeral goes between the two namesA Roman Numeral goes between the two names

4. Change the nonmetal ending to 4. Change the nonmetal ending to IDEIDE

EXAMPLES:EXAMPLES:

KBrKBr potassium bromide potassium bromide

NaNa22O O sodium oxidesodium oxide

MgS MgS magnesium sulfidemagnesium sulfide

Cu BrCu Br22 copper II bromide copper II bromide

AsAs22 O O55 arsenic V oxide arsenic V oxide

FeFe22 O O3 3 iron III oxideiron III oxide

How to Name a Molecular Formula:How to Name a Molecular Formula:Ex:Ex: COCO COCO22

1. Element with the (+) apparent charge comes 1st1. Element with the (+) apparent charge comes 1st carbon carboncarbon carbon

2. Second element ends in 2. Second element ends in IDEIDEcarbon oxide carbon oxidecarbon oxide carbon oxide

3. Use prefixes to distinguish between compounds & to 3. Use prefixes to distinguish between compounds & to show how many atoms of each element are presentshow how many atoms of each element are present

carbon carbon monmonoxide carbon oxide carbon didioxideoxide

Prefixes for Molecular Compounds:Prefixes for Molecular Compounds:

1. drop vowel on 1. drop vowel on prefix if element prefix if element starts with vowelstarts with vowel

EX: monooxide = EX: monooxide = monoxidemonoxide2. Don’t drop vowel 2. Don’t drop vowel

for for di and tri prefixesdi and tri prefixes

11 monomono Don’t use for first Don’t use for first named elementnamed element

22 didi Ex: COEx: CO

33 tritri carbon monoxidecarbon monoxide

44 tetratetra

55 pentapenta

66 hexahexa

77 heptahepta

88 octaocta

99 nonanona

1010 decadeca

EXAMPLES:EXAMPLES:

NONO

NONO22

NN22OO

NN22OO33

PClPCl55

CSCS22

SFSF66

nitrogen monoxidenitrogen monoxide

nitrogen dioxidenitrogen dioxide

dinitrogen monoxidedinitrogen monoxide

dinitrogen dinitrogen trioxidetrioxidephosphorus phosphorus pentachloridepentachloride carbon disulfidecarbon disulfide

sulfur hexafluoridesulfur hexafluoride

How to Write a Molecular Formula:How to Write a Molecular Formula:

1.1.Write down element symbolWrite down element symbol

2.2.Prefixes give you what subscripts to Prefixes give you what subscripts to useuse

EXAMPLES:EXAMPLES:

NONO

NONO22

NN22OO

NN22OO33

PClPCl55

CSCS22

SFSF66

nitrogen nitrogen dioxidedioxidedinitrogen monoxidedinitrogen monoxide

dinitrogen trioxidedinitrogen trioxide

phosphorus phosphorus pentachloridepentachloride carbon disulfidecarbon disulfide

sulfur hexafluoridesulfur hexafluoride

nitrogen monoxidenitrogen monoxide

REMINDER WHEN REMINDER WHEN WRITING FORMULAS:WRITING FORMULAS:

CHECK YOUR HOLY SHEETS CHECK YOUR HOLY SHEETS FOR ANY POLYATOMIC IONSFOR ANY POLYATOMIC IONS

TREAT THEM AS EITHER A TREAT THEM AS EITHER A CATION OR AN ANIONCATION OR AN ANION

An An ACIDACID is a substance that when put into water, is a substance that when put into water, gives away a hydrogen ion (Hgives away a hydrogen ion (H+1+1) to another ) to another substance in the water solution.substance in the water solution.

HCl + HHCl + H22O O HClHCl(aq)(aq)

There are two types of acids:There are two types of acids:

1. Binary acids-HCl1. Binary acids-HCl(aq)(aq)

2. Ternary acids-H2. Ternary acids-H22SOSO44(aq)(aq)

-polyatomic ions (ending in -polyatomic ions (ending in ateate))

-polyatomic ions (ending in -polyatomic ions (ending in iteite))