unit 3 atomic theory atom smallest particle possessing the properties of an element

Unit 3Unit 3Atomic TheoryAtomic Theory

AtomAtom

Smallest particle possessing theSmallest particle possessing the properties of an element.properties of an element.

NucleusNucleus

Dense, positively charged central Dense, positively charged central region that contains protons and region that contains protons and

neutrons.neutrons.

ProtonsProtons

Positively charged subatomic Positively charged subatomic particles that are found in the particles that are found in the

nucleusnucleus

NeutronsNeutrons

Neutral subatomic particles (have Neutral subatomic particles (have no electrical charge) that are no electrical charge) that are

found in the nucleus.found in the nucleus.

Electron CloudElectron Cloud

Different energy levels Different energy levels surrounding the atom’s nucleus surrounding the atom’s nucleus where electrons can be found.where electrons can be found.

ElectronsElectrons

Negatively charged subatomic Negatively charged subatomic particles that surround the particles that surround the

nucleus. nucleus.

Atomic NumberAtomic Number

The number of protons in an atom.The number of protons in an atom.

Atomic MassAtomic Mass

The relative average mass of an The relative average mass of an atom of an element as found in atom of an element as found in

nature.nature.

Atomic mass = # of protons + # of neutrons.

II: Atomic ParticlesII: Atomic Particles

ParticleParticle MassMass LocationLocation ChargeCharge

ProtonProton 1 AMU1 AMU NucleusNucleus PositivePositive

NeutronNeutron 1 AMU1 AMU NucleusNucleus NeutralNeutral

ElectronElectron 0 AMU0 AMU Electron Electron cloudcloud

NegativeNegative

IsotopesIsotopes

Atoms of the same element that Atoms of the same element that have a different number of have a different number of

neutrons.neutrons.

IsotopesIsotopes Two (2) or more atoms of the same element with Two (2) or more atoms of the same element with

a different mass.a different mass. Percent (%) abundance: Percent (%) abundance:

Protium, Deuterium, TritiumProtium, Deuterium, Tritium 99.985%, 0.015%, 0%99.985%, 0.015%, 0%

Self CheckSelf Check

1.1. What two subatomic particle are What two subatomic particle are found in the nucleus?found in the nucleus?

A. Neutrons and ElectronsA. Neutrons and Electrons

B. Protons and ElectronsB. Protons and Electrons

C. Neutrons and ProtonsC. Neutrons and Protons

D. Neutrons onlyD. Neutrons only

Self CheckSelf Check

2.2. The atomic number is equal to the The atomic number is equal to the _______._______.

A. Number of neutrons in an atom.A. Number of neutrons in an atom.

B. Number of electrons in an atom.B. Number of electrons in an atom.

C. Number of neutrons plus the C. Number of neutrons plus the number of protons in an atom.number of protons in an atom.

D. Number of protons in an atom. D. Number of protons in an atom.

Self CheckSelf Check

3.3. Isotopes are atoms of the same Isotopes are atoms of the same element that have a different element that have a different number of ______.number of ______.

A. NeutronsA. Neutrons

B. ProtonsB. Protons

C. ElectronsC. Electrons

D. All of the aboveD. All of the above

Self CheckSelf Check

4.4. The element with an atomic number The element with an atomic number of 14 is?of 14 is?

A. NitrogenA. Nitrogen

B. SiliconB. Silicon

C. AluminumC. Aluminum

D. SulfurD. Sulfur

Important Number StuffImportant Number Stuff

Atomic number is Atomic number is equal to the equal to the number of protons number of protons (and electrons in a (and electrons in a neutral atom)neutral atom)

Atomic Mass is the Atomic Mass is the sum of protons and sum of protons and neutronsneutrons

Examples…Examples…

ElementElement # # protonsprotons

# # neutronsneutrons

# # electronselectrons

Ave. Ave. Atomic Atomic massmass

BoronBoron 55 66 55 10.81110.811

SulfurSulfur 1616 1616 1616 32.00632.006

GoldGold 7979 118118 7979 196.96196.96

Sample—look at “2_weighted ave.”Sample—look at “2_weighted ave.”

Of 100 marbles: Of 100 marbles: – 25 have a mass of 2.00g25 have a mass of 2.00g– 75 have a mass of 3.00g75 have a mass of 3.00g– What is the average mass?What is the average mass?

25% = 0.2525% = 0.25 75% = 0.7575% = 0.75 (0.25 x 2.00) + (3.00 x 0.75) = Ave Mass(0.25 x 2.00) + (3.00 x 0.75) = Ave Mass 0.5 + 2.25 = 2.750.5 + 2.25 = 2.75

Sample with AtomsSample with Atoms

Copper 63 amu = 69.17%Copper 63 amu = 69.17% Copper 65 amu = 30.83%Copper 65 amu = 30.83% Calculate the Average Calculate the Average

atomic massatomic mass

Continued…Continued…

Copper 63 amu = 69.17Copper 63 amu = 69.17 Copper 65 amu = 30.83Copper 65 amu = 30.83 Calculate the Average atomic massCalculate the Average atomic mass

(63 x 0.6917) + (65 x 0.3083)(63 x 0.6917) + (65 x 0.3083) 63.617 AMU63.617 AMU

– Check on periodic tableCheck on periodic table

IonsIons

Electrically charged atoms or Electrically charged atoms or groups of atoms.groups of atoms.

Cations = positively chargedCations = positively charged

Anions = negatively chargedAnions = negatively charged

I: Models of the atom over timeI: Models of the atom over time

DemocritusDemocritus: : fifth century BC Philosopherfifth century BC Philosopher– First to describe matter as made of tiny First to describe matter as made of tiny

particlesparticles

John DaltonJohn Dalton:: “Billiard ball” theory 1803 “Billiard ball” theory 1803– Atom = small solid sphereAtom = small solid sphere

In an element = all the same “sphere”In an element = all the same “sphere”Different elements = different “sphere”Different elements = different “sphere”Compounds = different spheres combined in Compounds = different spheres combined in

different ratiosdifferent ratios

Continued…Continued…

JJ Thompson:JJ Thompson: 1897 1897 “Plum Pudding” “Plum Pudding” modelmodel– Atom = sphere of + Atom = sphere of +

and – particlesand – particles– Discovered the Discovered the

electron = Nobel electron = Nobel prizeprize

ContinuedContinued Ernest RutherfordErnest Rutherford: :

19081908– Atom = mostly Atom = mostly

empty spaceempty space + nucleus+ nucleus - electrons outside- electrons outside

Niels Bohr:Niels Bohr: 1913 1913– Electrons traveled Electrons traveled

in circular orbitsin circular orbits

Continued…Continued… Electron Cloud Electron Cloud

ModelModel: 1920’s : 1920’s – Atom = Dense Atom = Dense

nucleus of + protons nucleus of + protons and neutral neutrons.and neutral neutrons.

– Electrons surround Electrons surround nucleus in “clouds” of nucleus in “clouds” of different NRG levels.different NRG levels.

(NRG =Numerical (NRG =Numerical Renormalization Renormalization Group)Group)

Elements on the Periodic TableElements on the Periodic Table

1Hydrogen

H1.008

Self CheckSelf Check

5.5. Draw a picture of what Iron in its Draw a picture of what Iron in its neutral state would look like on the neutral state would look like on the periodic table.periodic table.Hint:

Self Check AnswersSelf Check Answers

1. C1. C

2. D2. D

3. A3. A

4. B4. B

5.5.26Iron

Fe55.85

III. Molar III. Molar ConversionsConversions

A. What is the Mole?A. What is the Mole?

A counting number (like a dozen)A counting number (like a dozen)

Avogadro’s number (NAvogadro’s number (NAA))

1 mol = 1 mol = 6 6 10 102323 items items

A large amount!!!!A large amount!!!!

1 mole of hockey pucks would 1 mole of hockey pucks would equal the mass of the moon!equal the mass of the moon!

A. What is the Mole?A. What is the Mole?

1 mole of pennies would cover 1 mole of pennies would cover the Earth 1/4 mile deep!the Earth 1/4 mile deep!

1 mole of basketballs would fill 1 mole of basketballs would fill a bag the size of the earth!a bag the size of the earth!

B. Molar MassB. Molar Mass The mass of 1 mole of an element The mass of 1 mole of an element

or compound. Round to nearest or compound. Round to nearest

whole number (except chlorine)whole number (except chlorine)

Atomic weight label:Atomic weight label:– amu/atom or g/molamu/atom or g/mol

Molecular weight label:Molecular weight label:

– amu/molecule or g/molamu/molecule or g/mol

B. Molar Mass ExamplesB. Molar Mass Examples

carboncarbon

aluminumaluminum

zinczinc

12 g/mol12 g/mol

27 g/mol27 g/mol

65 g/mol65 g/mol

B. Molar Mass ExamplesB. Molar Mass Examples

waterwater

sodium chloridesodium chloride

– HH22OO

– 2(1) + 16 = 18 g/mol2(1) + 16 = 18 g/mol

– NaClNaCl– 23 + 35.5 = 58.5 g/mol23 + 35.5 = 58.5 g/mol

B. Molar Mass ExamplesB. Molar Mass Examples

sodium bicarbonatesodium bicarbonate

sucrosesucrose

– NaHCONaHCO33

– 23 + 1 + 12 + 3(16) 23 + 1 + 12 + 3(16)

= 84 g/mol= 84 g/mol

– CC1212HH2222OO1111

– 12(12) + 22(1) + 11(16) 12(12) + 22(1) + 11(16)

= 342 g/mol= 342 g/mol

C. Molar ConversionsC. Molar Conversions

molar mass

(g)

MASS

IN

GRAMS

MOLESNUMBER

OF

PARTICLES

6 1023

(atoms/molecules)

C. Molar Conversion ExamplesC. Molar Conversion ExamplesHow many moles of carbon How many moles of carbon

are in 26 g of carbon? are in 26 g of carbon?

26 g C26 g C 1 mol C1 mol C

12 g C12 g C= 2.17 mol C= 2.17 mol C

C. Molar Conversion ExamplesC. Molar Conversion ExamplesHow many molecules are in How many molecules are in

2.50 moles of C2.50 moles of C1212HH2222OO1111? ?

2.50 mol2.50 molCC1212HH2222OO1111

6 6 10 102323

moleculesmolecules

1 mol1 mol= 1.5 = 1.5 10 102424

moleculesmolecules CC1212HH2222OO1111

C. Molar Conversion ExamplesC. Molar Conversion ExamplesFind the mass of 2.5 moles of Find the mass of 2.5 moles of

NaHCONaHCO33. .

2.5 mol2.5 molNaHCONaHCO33 84 g84 g

1 mol1 mol

= 210 g NaHCO= 210 g NaHCO33

Patterns on the Periodic Table