Unit 3Unit 3

Periodic TablePeriodic Table

Robert BoyleRobert Boyle

The first scientist to be The first scientist to be concerned with careful concerned with careful measurementsmeasurements

Did not hold any Did not hold any assumptions as to how assumptions as to how many elements there many elements there werewere

Decided that only Decided that only experimentation would experimentation would telltell

Element 101Element 101 Basic building blocksBasic building blocks

1 atom or many atoms of the same kind = an element1 atom or many atoms of the same kind = an element Presently there are about 120 elementsPresently there are about 120 elements

88 occur naturally88 occur naturally The 9 most abundant make up 98% of the earth’s massThe 9 most abundant make up 98% of the earth’s mass

Oxygen 49%Oxygen 49% Silicon 25 %Silicon 25 % Aluminum, Iron, Calcium, Sodium, Potassium, Magnesium, and Aluminum, Iron, Calcium, Sodium, Potassium, Magnesium, and

HydrogenHydrogen Diatomic molecules are ELEMENTS!Diatomic molecules are ELEMENTS!

Two atoms of the same element bonded together… know them!Two atoms of the same element bonded together… know them!

Mendeleev's Periodic Table: The first one!Mendeleev's Periodic Table: The first one!

- Can you see any patterns?- Can you see any patterns?

- How was it arranged?- How was it arranged?

Build Your Own Table Time!!Build Your Own Table Time!!

- In groups of 2-3 you In groups of 2-3 you will be building your will be building your own tablesown tables

- Be sure to write down Be sure to write down information that will information that will help you organize this help you organize this again!again!

What’s on the table?What’s on the table? Atomic numberAtomic number

Number of protonsNumber of protons Defines the elementDefines the element

Atomic MassAtomic Mass The average mass of all the The average mass of all the

isotopes of that elementisotopes of that element Atomic SymbolAtomic Symbol NameName Mass NumberMass Number

The mass of a single isotope The mass of a single isotope of an elementof an element

Color Time!!!!!Color Time!!!!!

Elemental NomenclatureElemental Nomenclature

Elemental name are Elemental name are often derived from often derived from Latin or Greek wordsLatin or Greek words Aurum – shining Aurum – shining

dawndawn Plumbum – heavyPlumbum – heavy Bromus - stenchBromus - stench

26 Common Elements and Their 26 Common Elements and Their Symbols… You MUST know these!Symbols… You MUST know these!

Atomic AnatomyAtomic Anatomy

- ProtonProton- p+p+- NucleusNucleus- 1 AMU1 AMU

- ElectronElectron- e-e-- Electron cloudElectron cloud- 1/1847 AMU1/1847 AMU

- NeutronNeutron- nn- NucleusNucleus- 1 AMU1 AMU

Using Your TableUsing Your TableCalculating Protons:Calculating Protons:

- Atomic number- Atomic number

- Same as electrons in neutral atoms- Same as electrons in neutral atoms

Calculating Electrons:Calculating Electrons:

- Same as protons in neutral atoms- Same as protons in neutral atoms

Calculating Neutrons:Calculating Neutrons:

- M# - A# = # of neutrons- M# - A# = # of neutrons

- DO NOT USE atomic mass, must use mass #- DO NOT USE atomic mass, must use mass #

Element QuizElement Quiz

Provide the symbol for the following elements:

1.Aluminum2.Bromine3.Potassium4.Sodium5.Lead6.Copper7.Nitrogen8.Zinc

Provide the name for the following symbols:

9. Mg10. Ag11. Cr12. I13. Sn14. F15. S16. Hg

Spelling Does Count!

Atomic Structure Quiz

Provide the following 5 pieces of information for the given atoms: #p+, #n0, #e-, mass #, atomic #

LOOK AT THE CHALKBOARD!

Isotopes and the Nucleus

Isotopes are atoms with the same number of protons, but different numbers of neutrons.

Do they have the same mass?

Are they the same element?

How many protons?

How many neutrons?

-Isotopes are described by their mass number

-Examples:

-C-12 and C-14

Isotope Math

Calculating Mass # #n0 + #p+ = mass #

Calculating Average Mass of given isotopes (sum of mass #s)/(# of atoms) = Ave Mass

Calculating Weighted Masses (by percent) (%A)(Mass #A) + (%B)(Mass #B) + …= Weighted Mass

Try Some!!

Calculate Average Mass 1 atom has a mass of 10 1 atom has a mass of 12 1 atom has a mass of 8 30/3=10 AMU

5 atoms have a mass of 10 each 17 atoms have a mass of 12 each 3 atoms have a mass of 8 each 278/25 = 11.1 AMU

5 x 10 = 5017 x 12 = 2043 x 8 = 24

= 278

One more!One more!

39% have a mass of 10 AMU39% have a mass of 10 AMU 11% have a mass of 12 AMU11% have a mass of 12 AMU 50% have a mass of 8 AMU50% have a mass of 8 AMU Total Total

3.9 + 1.32 + 4 = 9.22 AMU3.9 + 1.32 + 4 = 9.22 AMU

Isotopes of B WS

From the Nucleus to the Cloud

Electrons are negatively charged

Electrons are virtually massless

Electrons are FAST! Electrons are quantized

Electrons inhabit orbitals (aka rings or shells)

Outer Atomic Structure

- Electrons “live” outside the nucleus- Electron Shells (Bohr)- Electron Cloud (Schrodinger)

- The outermost electrons are valence electrons- All other electrons are core electrons

Core e- = (Atomic #) – (Valence e-)

The importance of valence The importance of valence electronselectrons

Valence electrons are on Valence electrons are on the outer shellthe outer shell

They are the electrons that They are the electrons that are involved in reactionsare involved in reactions

We can describe chemical We can describe chemical behavior by knowing the behavior by knowing the number of valence number of valence electronselectrons

Perioic table and Perioic table and electrons… using your electrons… using your table again!table again!

IonsIons

Ions are atoms that are Ions are atoms that are no longer neutral, they no longer neutral, they have a chargehave a charge

Electrons can be Electrons can be removed or addedremoved or added Removed = +Removed = + Added = -Added = -

Ions are usually Ions are usually unstable and very unstable and very reactivereactive

The “address” for the electron in a The “address” for the electron in a neutral atomneutral atom

Ground State Electron Ground State Electron ConfigurationsConfigurations

Electron QuestionsElectron Questions

1.1. What is the “address” for electrons in an What is the “address” for electrons in an atom?atom?

2.2. How can we find the electron’s “address”How can we find the electron’s “address”

Valence shellValence shell

Valence electronsValence electrons

Core electronsCore electrons

GroupsGroups

PeriodsPeriods

ShellsShells

Use the following terms in 2-4 sentences that describe how we can find the following on the periodic table. You may work with 1 partner.

Purple – The final electrons for these elements are in the “s” orbitalPurple – The final electrons for these elements are in the “s” orbitalPale Yellow – The final electrons for these elements are in the “p” orbitalPale Yellow – The final electrons for these elements are in the “p” orbital

Teal – The final electrons for these elements are in the “d” orbitalTeal – The final electrons for these elements are in the “d” orbitalLight Green – The final electrons for these elements are in the “f” orbitalLight Green – The final electrons for these elements are in the “f” orbital

Orbital Filling - Aufbau Orbital Filling - Aufbau PrinciplePrinciple

-Electrons will fill the LOWEST energy levels first.-This is known as the Aufbau (building up) principle.-Electron filling follows the diagram

“s” orbitals can hold up to 2 electrons“p” orbitals can hold up to 6 electrons“d” orbitals can hold up to 10 electrons“f” orbitals can hold up to 14 electrons

NOTICE: Certain orbital types ONLY show up in certain shells

The order ends up: 1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p67s25f146d107p6

Electron Configurations and Dot Electron Configurations and Dot Diagrams:Diagrams:

Show the electron configuration and dot diagram for Show the electron configuration and dot diagram for the following:the following:

LiLi OO

BeBe NeNe

NaNa TiTi

Models of the AtomModels of the Atom

Solid Model (Dalton)Solid Model (Dalton) Plum Pudding Model (Thomson)Plum Pudding Model (Thomson) Rutherford ModelRutherford Model Bohr ModelBohr Model Cloud Model (Schrodinger)Cloud Model (Schrodinger)

Dalton’s Atomic TheoryDalton’s Atomic Theory

English Science English Science teacher in the 1800’s teacher in the 1800’s

Offered a 5 part Offered a 5 part theory for the theory for the structure of an atomstructure of an atom

Dalton’s Theory

1. Elements are made up of small particles called atoms.2. All atoms of a given element are identical.3. The atoms of a given element are different from those of

any other element.4. Atoms of one element can combine with atoms from another

element to form compounds. A given compound always has the same relative numbers and types of atoms.

5. Atoms are indivisible in chemical processes. That is, atoms are not created or destroyed in chemical reactions. A chemical reaction simply changes the way atoms are grouped together.

Plum Pudding ModelPlum Pudding Model

Proposed by J.J. Thomson Proposed by J.J. Thomson in the 1800’sin the 1800’s

First experimental proof First experimental proof of different charges in an of different charges in an atomatom

Said the atom looked like Said the atom looked like “pudding with plums in “pudding with plums in it”it” Plums were the evenly Plums were the evenly

distributed positive and distributed positive and negative charges.negative charges.

Rutherford’s ModelRutherford’s Model

Proof of a solid nucleusProof of a solid nucleus Most particles moved Most particles moved

through the foil through the foil untoucheduntouched Foil was mostly empty Foil was mostly empty

spacespace Some particles were Some particles were

deflecteddeflected There must be a solid, There must be a solid,

dense nucleus with a dense nucleus with a positive chargepositive charge

Niels Bohr’s Model of the AtomNiels Bohr’s Model of the Atom

Based on data obtained from Based on data obtained from the atomic spectrumthe atomic spectrum

Electrons must be Electrons must be “quantized”“quantized” Only inhabit specific levels of Only inhabit specific levels of

energy (quanta, orbitals)energy (quanta, orbitals) Must be several levelsMust be several levels Atoms can jump from one Atoms can jump from one

level to another, but cannot level to another, but cannot inhabit in between levelsinhabit in between levels

Incorporated ideas from Incorporated ideas from Quantum PhysicsQuantum Physics

Bright Line Spectrum of HydrogenBright Line Spectrum of Hydrogen

Schrodinger’s Cloud ModelSchrodinger’s Cloud Model

Schrodinger was a Schrodinger was a physicistphysicist

Calculated the probability Calculated the probability of an electron being in of an electron being in each leveleach level

Plotted the probabilities Plotted the probabilities and determined a function and determined a function to calculate the position or to calculate the position or energy of an electronenergy of an electron

This is the model most This is the model most scientists refer to todayscientists refer to today