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