Atomic Structure

Atomic StructureAtomic Structure

Atoms and their structureAtoms and their structure

History of the atomHistory of the atom Not the history of atom, but the history of the Not the history of atom, but the history of the

idea of the atom idea of the atom Original idea Ancient Greece (400 B.C..)Original idea Ancient Greece (400 B.C..) Democritus and Leucippus - two Greek Democritus and Leucippus - two Greek

philosophers philosophers

History of AtomHistory of Atom Looked at beachLooked at beach Made of sandMade of sand Cut sand - smaller sandCut sand - smaller sand

Smallest possible Smallest possible

piece?piece?Atomos - not to be cutAtomos - not to be cut

Another GreekAnother Greek Aristotle - Famous philosopherAristotle - Famous philosopher All substances are made of 4 elementsAll substances are made of 4 elements Fire - hotFire - hot Air - lightAir - light Earth - cool, heavyEarth - cool, heavy Water - wetWater - wet Blend these in different proportions to Blend these in different proportions to

get all substances get all substances

Who Was Right?Who Was Right? Greek society was slave basedGreek society was slave based It was beneath the famous to work with their It was beneath the famous to work with their

handshands They did not experimentThey did not experiment Greeks settled disagreements by argumentGreeks settled disagreements by argument Aristotle was more famousAristotle was more famous He wonHe won His ideas carried through to the middle ages.His ideas carried through to the middle ages. Alchemists therefore tried to change lead to Alchemists therefore tried to change lead to

goldgold

Who’s Next?Who’s Next? Late 1700’s - John Dalton - a famous Late 1700’s - John Dalton - a famous

English chemist conducted experimentsEnglish chemist conducted experiments Summarized results of his experiments Summarized results of his experiments

and those of other’sand those of other’s Where?Where? In Dalton’s Atomic TheoryIn Dalton’s Atomic Theory Combined ideas of elements with that of Combined ideas of elements with that of

atomsatoms

Dalton’s Atomic TheoryDalton’s Atomic Theory All All mattermatter is made of tiny is made of tiny indivisibleindivisible

particles called atoms.particles called atoms. Atoms of the same element are identical, Atoms of the same element are identical,

those of different atoms are different.those of different atoms are different. Atoms of different elements combine in Atoms of different elements combine in

whole number ratios to form compoundswhole number ratios to form compounds Chemical reactions involve the Chemical reactions involve the

rearrangement of atoms. No new atoms rearrangement of atoms. No new atoms are created or destroyed.are created or destroyed.

Law of Definite ProportionsLaw of Definite Proportions Each compound has a specific ratio of Each compound has a specific ratio of

elementselements It is a ratio by mass It is a ratio by mass Water is always 8 grams of oxygen for Water is always 8 grams of oxygen for

each gram of hydrogen each gram of hydrogen

Law of Multiple ProportionsLaw of Multiple Proportions If two elements form more that one If two elements form more that one

compound, the ratio of the second compound, the ratio of the second element that combines with 1 gram of element that combines with 1 gram of the first element in each is always a the first element in each is always a simple whole number.simple whole number.

Parts of AtomsParts of Atoms J. J. Thomson - English physicist. 1897J. J. Thomson - English physicist. 1897 Made a piece of equipment called a Made a piece of equipment called a

cathode ray tube.cathode ray tube. It is a vacuum tube - all the air has been It is a vacuum tube - all the air has been

pumped out.pumped out.

Thomson’s ExperimentThomson’s Experiment

Voltage source

+-

Vacuum tube

Metal Disks


Voltage source

+-


Voltage source

+-


Voltage source

+-

Passing an electric current makes a beam Passing an electric current makes a beam appear to move from the negative to the appear to move from the negative to the positive endpositive end


Voltage source

+-



Voltage source

+-



Voltage source

+-



Voltage source

+-

Voltage source


By adding an electric field By adding an electric field

Voltage source



+

-

Voltage source



+

-

Voltage source



+

-

Voltage source



+

-

Voltage source



+

-

Voltage source


By adding an electric field he found that the By adding an electric field he found that the moving pieces were negative moving pieces were negative

+

-

J. J. Thomsom’s ModelJ. J. Thomsom’s Model Discovered the Discovered the

electronelectron Couldn’t find positive Couldn’t find positive

(for a while) (for a while) Said the atom was Said the atom was

like plum puddinglike plum pudding A bunch of positive A bunch of positive

stuff, with the stuff, with the electrons able to be electrons able to be removed removed

Other piecesOther pieces Proton - positively charged pieces Proton - positively charged pieces

1840 times heavier than the electron1840 times heavier than the electron Neutron - no charge but the same mass Neutron - no charge but the same mass

as a proton.as a proton. Where are the pieces?Where are the pieces?

Rutherford’s experimentRutherford’s experiment Ernest Rutherford - another famous English Ernest Rutherford - another famous English

physicist. (1910)physicist. (1910) He believed in the plum pudding model of the He believed in the plum pudding model of the

atom.atom. He wanted to see how big the electrons He wanted to see how big the electrons

(plums) were.(plums) were. Used radioactive Uranium.Used radioactive Uranium. Alpha particles - positively charged pieces Alpha particles - positively charged pieces

given off by uranium given off by uranium 22HeHe44

Shot them at gold foil which can be made a Shot them at gold foil which can be made a few atoms thick few atoms thick

Rutherford’s experimentRutherford’s experiment When the alpha particles hit a florescent When the alpha particles hit a florescent

screen, it glows.screen, it glows. Here’s what the set up of the Here’s what the set up of the

experiment looked like.experiment looked like.

Lead block

Uranium

Gold Foil

Florescent Screen

He ExpectedHe ExpectedThe alpha particles to pass through The alpha particles to pass through

without changing direction very muchwithout changing direction very much

BecauseBecause

– The positive charges were spread out The positive charges were spread out evenly. Alone they were not enough evenly. Alone they were not enough to stop the alpha particlesto stop the alpha particles

What he expected

Because

Because, he thought the mass was evenly distributed in the atom

Because, he thought the mass was evenly distributed in the atom

What he got

Conclusions of Rutherford's Experiment:

+

1.1. Atom is mostly emptyAtom is mostly emptyBecause most particles passed straight throughBecause most particles passed straight through

2.2. Small dense,Small dense, positive piecepositive piece

at centerat centerBecause Alpha particles Because Alpha particles

are deflected by theare deflected by the

nucleus it if they get nucleus it if they get

close enoughclose enough

+

Bohr ModelBohr Model Planetary Model or Heliocentric ModelPlanetary Model or Heliocentric Model Places the Places the nucleusnucleus in the in the centercenter of the of the

atom like the sun in the center of the atom like the sun in the center of the universeuniverse

Places the Places the electronselectrons in in orbitalsorbitals revolving around the nucleus, like the revolving around the nucleus, like the planets revolve around the sun. planets revolve around the sun. (fixed (fixed paths)paths)

Modern ViewModern View The atom is mostly The atom is mostly

empty spaceempty space Two regionsTwo regions

– Nucleus:Nucleus:» protons and neutronsprotons and neutrons

– Electron cloud:Electron cloud:» region where you might find region where you might find

an electron based on an electron based on mathematical probability.mathematical probability.

Density and the AtomDensity and the Atom Since most of the particles went Since most of the particles went

through, it was mostly empty.through, it was mostly empty. Because the pieces turned so much, Because the pieces turned so much,

the positive pieces were heavy.the positive pieces were heavy. Small volume, big mass, big densitySmall volume, big mass, big density This small dense positive area is the This small dense positive area is the

nucleusnucleus Scale: marble in a football field.Scale: marble in a football field.

Subatomic particlesSubatomic particles

Electron

Proton

Neutron

Name Symbol ChargeRelative mass

Actual mass (g)

e-

p+

n0

-1

+1

0

1/1840

1

1

9.11 x 10-28

1.67 x 10-24

1.67 x 10-24

Structure of the AtomStructure of the Atom There are two regionsThere are two regions

– The nucleusThe nucleus» With protons and neutrons With protons and neutrons

» Positive chargePositive charge

» Almost all the massAlmost all the mass

– Electron cloud- Most of the volume of Electron cloud- Most of the volume of an atoman atom

» The region where the electron can be foundThe region where the electron can be found

Size of an atomSize of an atom Atoms are small.Atoms are small. Measured in picometers, 10Measured in picometers, 10-12-12 meters meters Hydrogen atom, 32 pm radiusHydrogen atom, 32 pm radius Nucleus tiny compared to atom Nucleus tiny compared to atom (marble in a football (marble in a football

field)field)

Radius of the nucleus near 10Radius of the nucleus near 10-15-15m.m.

Counting the PiecesCounting the Pieces Atomic Number Atomic Number = number of protons= number of protons

– # of protons determines kind of atom# of protons determines kind of atom

– The # of protons is the same as the The # of protons is the same as the number of electrons in a neutral number of electrons in a neutral atomatom

Mass Number = Mass Number =

the number of protons + neutronsthe number of protons + neutrons

End of Part OneEnd of Part One

Atomic Structure - Part TwoAtomic Structure - Part Two

SymbolsSymbols Contain the symbol of the element, the Contain the symbol of the element, the

mass number and the atomic numbermass number and the atomic number

SymbolsSymbols Contain the symbol of the element, the Contain the symbol of the element, the

mass number and the atomic numbermass number and the atomic number

X Massnumber

Atomicnumber

SymbolsSymbols Find the Find the

– number of protonsnumber of protons

– number of neutronsnumber of neutrons

– number of electronsnumber of electrons

– Atomic numberAtomic number

– Mass NumberMass Number

F19 9

SymbolsSymbols Find the Find the

–number of protonsnumber of protons

–number of neutronsnumber of neutrons

–number of electronsnumber of electrons

–Atomic numberAtomic number

–Mass NumberMass Number

Br80 35

SymbolsSymbols if an element has an atomic if an element has an atomic

number of 34 and a mass number number of 34 and a mass number of 78 what is the of 78 what is the


–number of neutronsnumber of neutrons


–Complete symbolComplete symbol

Se

SymbolsSymbols if an element has 91 protons and if an element has 91 protons and

140 neutrons what is the 140 neutrons what is the


–Mass numberMass number



Pa

SymbolsSymbols if an element has 78 electrons and if an element has 78 electrons and

117 neutrons what is the 117 neutrons what is the


–Mass numberMass number



Pt

Naming IsotopesNaming Isotopes Put the mass number after the name of Put the mass number after the name of

the elementthe element carbon- 12carbon- 12 carbon -14carbon -14 uranium-235uranium-235

IsotopesIsotopes Dalton was wrong.Dalton was wrong. Atoms of the same element can have Atoms of the same element can have

different numbers of neutronsdifferent numbers of neutrons Different mass numbersDifferent mass numbers Called Called isotopes isotopes (do not confuse with (do not confuse with

allotropes)allotropes)

Atomic MassAtomic Mass How heavy is an atom of oxygen?How heavy is an atom of oxygen?

– There are different kinds of oxygen atoms.There are different kinds of oxygen atoms.– More concerned with More concerned with average average atomic mass.atomic mass.– Weighted average based on the Weighted average based on the

abundances of all the naturally occurring abundances of all the naturally occurring isotopes in nature.isotopes in nature.

– Don’t use grams because the numbers Don’t use grams because the numbers would be too small. would be too small.

Measuring Atomic MassMeasuring Atomic Mass Unit is the Unit is the Atomic Mass Unit Atomic Mass Unit (amu)(amu)

– AMU is based on the C-12 atom. It is AMU is based on the C-12 atom. It is one twelfth the mass of a carbon-12 one twelfth the mass of a carbon-12 atom. atom.

– Each isotope has its own atomic Each isotope has its own atomic mass we need the average from mass we need the average from percent abundance.percent abundance.

It all averages outIt all averages outTestTest Student AStudent A Student BStudent B

11 9595 8989

22 7474 8888

33 9595 8888

44 9595 8787

55 7474 8888

66 9595 8888

Avg. GradeAvg. Grade

Test 6 Counts 50%Test 6 Counts 50%Student AStudent A

95 x 10% =95 x 10% = 74 x 10% =74 x 10% = 95 x 10% =95 x 10% = 95 x 10% =95 x 10% = 74 x 10% =74 x 10% = 95 x 50% =95 x 50% =

____________________

Student BStudent B 89 x 10% =89 x 10% = 88 x 10% =88 x 10% = 88 x 10% =88 x 10% = 87 x 10% =87 x 10% = 88 x 10% =88 x 10% = 88 x 50% =88 x 50% =

____________________

Student AStudent A 95 x .1 =95 x .1 = 74 x .1 =74 x .1 = 95 x .1 =95 x .1 = 95 x .1 =95 x .1 = 74 x .1 =74 x .1 = 95 x .5 =95 x .5 =

____________________

Atomic MassAtomic Mass Calculate the atomic mass of copper if Calculate the atomic mass of copper if

copper has two isotopes. 69.1% has a mass copper has two isotopes. 69.1% has a mass of 62.93 amu and the rest has a mass of of 62.93 amu and the rest has a mass of 64.93 amu.64.93 amu.

Atomic MassAtomic Mass Magnesium has three isotopes. 78.99% Magnesium has three isotopes. 78.99%

magnesium 24 with a mass of 23.9850 magnesium 24 with a mass of 23.9850 amu, 10.00% magnesium 25 with a mass of amu, 10.00% magnesium 25 with a mass of 24.9858 amu, and the rest magnesium 26 24.9858 amu, and the rest magnesium 26 with a mass of 25.9826 amu. What is the with a mass of 25.9826 amu. What is the atomic mass of magnesium?atomic mass of magnesium?

If not told otherwise, the mass of the If not told otherwise, the mass of the isotope is the mass number in amu isotope is the mass number in amu

Atomic MassAtomic Mass Is not a whole number because it is an Is not a whole number because it is an

average. average. The decimal numbers on the periodic The decimal numbers on the periodic

table are based on the weighted table are based on the weighted average of all the known naturally average of all the known naturally occurring isotopes.occurring isotopes.

The EndThe End

Bohr’s ModelBohr’s Model

Nucleus

Electron

Orbit

Energy Levels

Bohr’s ModelBohr’s Model

Nucleus

Electron

Orbit

Energy Levels

Bohr’s ModelBohr’s ModelIn

crea

sing

ene

rgy

Nucleus

First

Second

Third

Fourth

Fifth

} Further away Further away

from the from the nucleus means nucleus means more energy.more energy.

There is no “in There is no “in between” between” energyenergy

Energy LevelsEnergy Levels

The Quantum Mechanical ModelThe Quantum Mechanical Model

Energy is quantized. It comes in chunks.Energy is quantized. It comes in chunks. QuantaQuanta - the amount of energy needed to - the amount of energy needed to

move from one energy level to another.move from one energy level to another. Quantum leap in energy.Quantum leap in energy. Schrödinger derived an equation that Schrödinger derived an equation that

described the energy and position of the described the energy and position of the electrons in an atomelectrons in an atom

Treated electrons as wavesTreated electrons as waves

a mathematical solutiona mathematical solution It is not like anything you can It is not like anything you can

see.see.


Does have energy levelsDoes have energy levels for electrons. for electrons.

Orbits are not circular.Orbits are not circular. It can only tell us theIt can only tell us the

probability of finding probability of finding an electron a certain distance from the an electron a certain distance from the nucleus.nucleus.


The electron is found The electron is found inside a blurry inside a blurry “electron cloud”“electron cloud”

An area where there An area where there is a chance of finding is a chance of finding an electron.an electron.

Draw a line at 90 %Draw a line at 90 %


Atomic OrbitalsAtomic Orbitals Principal Quantum NumberPrincipal Quantum Number (n) = the energy (n) = the energy

level of the electron.level of the electron. Within each energy level the complex math Within each energy level the complex math

of Schrödinger's equation describes several of Schrödinger's equation describes several shapes.shapes.

These are called These are called atomic orbitals. atomic orbitals. – To calculate number of orbitals : nTo calculate number of orbitals : n22

– To calculate maximum electrons per energy level: 2nTo calculate maximum electrons per energy level: 2n22

Regions where there is a high probability of Regions where there is a high probability of finding an electron.finding an electron.

1 s orbital for1 s orbital for every energy level every energy level Spherical Spherical

shapedshaped

Each s orbital can hold 2 electronsEach s orbital can hold 2 electrons Called the 1s, 2s, 3s, etc.. orbitals.Called the 1s, 2s, 3s, etc.. orbitals.

S orbitalsS orbitals

P orbitalsP orbitals Start at the second energy level Start at the second energy level 3 different directions3 different directions 3 different shapes (dumbell)3 different shapes (dumbell) Each can hold 2 electronsEach can hold 2 electrons

P OrbitalsP Orbitals

D orbitalsD orbitals Start at the third energy level Start at the third energy level 5 different shapes5 different shapes Each can hold 2 electronsEach can hold 2 electrons

F orbitalsF orbitals

Start at the fourth energy levelStart at the fourth energy level Have seven different shapesHave seven different shapes 2 electrons per shape2 electrons per shape

F orbitalsF orbitals

Images

J mol

SummarySummary

s

p

d

f

# of shapes

Max electrons

Starts at energy level

1 2 1

3 6 2

5 10 3

7 14 4

Filling orderFilling order Lowest energy fill first.Lowest energy fill first. The energy levels overlapThe energy levels overlap The orbitals The orbitals do notdo not fill up order of energy fill up order of energy

level.level. Counting systemCounting system

– Each box is an orbital shapeEach box is an orbital shape

– Room for two electronsRoom for two electrons

Incr

easi

ng e

nerg

y

1s

2s

3s

4s

5s6s

7s

2p

3p

4p

5p

6p7p

3d

4d

5d

6d

4f

5f

Incr

easi

ng e

nerg

y

1s

2s

3s

4s

5s6s

7s

2p

3p

4p

5p

6p

3d

4d

5d

7p 6d

4f

5f

Electron ConfigurationsElectron Configurations Aufbrau principleAufbrau principle- electrons enter the - electrons enter the

lowest energy first.lowest energy first. Pauli Exclusion PrinciplePauli Exclusion Principle- at most 2 - at most 2

electrons per orbital - different spinselectrons per orbital - different spins Heisenberg’s Principle- Heisenberg’s Principle- we do not know we do not know

the precise location of an electron only a the precise location of an electron only a probability of where the electron is in the probability of where the electron is in the orbital cloud.orbital cloud.

Electron ConfigurationElectron Configuration Hund’s RuleHund’s Rule- When electrons occupy - When electrons occupy

orbitals of equal energy they don’t pair orbitals of equal energy they don’t pair up until they have to . (up, up, up, then up until they have to . (up, up, up, then down, down, down.)down, down, down.)

Phosphorus electron config. Phosphorus electron config.

The first to electrons The first to electrons go into the 1s orbitalgo into the 1s orbital

Notice the opposite Notice the opposite spinsspins

only 13 moreonly 13 more

Incr

easi

ng e

nerg

y

1s

2s

3s

4s

5s6s

7s

2p

3p

4p

5p

6p

3d

4d

5d

7p 6d

4f

5f

The next electrons The next electrons go into the 2s orbitalgo into the 2s orbital

only 11 moreonly 11 more

Incr

easi

ng e

nerg

y

1s

2s

3s

4s

5s6s

7s

2p

3p

4p

5p

6p

3d

4d

5d

7p 6d

4f

5f

• The next electrons go into the 2p orbital

• only 5 more

Incr

easi

ng e

nerg

y

1s

2s

3s

4s

5s6s

7s

2p

3p

4p

5p

6p

3d

4d

5d

7p 6d

4f

5f

• The next electrons go into the 3s orbital

• only 3 more

Incr

easi

ng e

nerg

y

1s

2s

3s

4s

5s6s

7s

2p

3p

4p

5p

6p

3d

4d

5d

7p 6d

4f

5f

Incr

easi

ng e

nerg

y

1s

2s

3s

4s

5s6s

7s

2p

3p

4p

5p

6p

3d

4d

5d

7p 6d

4f

5f

• The last three electrons go into the 3p orbitals.

• They each go into separate shapes

• 3 unpaired electrons

• 1s22s22p63s23p3

The easy way to remember The easy way to remember

1s2s 2p3s 3p 3d4s 4p 4d 4f

5s 5p 5d 5f6s 6p 6d 6f7s 7p 7d 7f

• 1s2

• 2 electrons

Fill from the bottom up following Fill from the bottom up following the arrowsthe arrows

1s2s 2p3s 3p 3d4s 4p 4d 4f

5s 5p 5d 5f6s 6p 6d 6f7s 7p 7d 7f

• 1s2 2s2

• 4 electrons


1s2s 2p3s 3p 3d4s 4p 4d 4f

5s 5p 5d 5f6s 6p 6d 6f7s 7p 7d 7f

• 1s2 2s2 2p6 3s2

• 12 electrons


1s2s 2p3s 3p 3d4s 4p 4d 4f

5s 5p 5d 5f6s 6p 6d 6f7s 7p 7d 7f

• 1s2 2s2 2p6 3s2

3p6 4s2

• 20 electrons


1s2s 2p3s 3p 3d4s 4p 4d 4f

5s 5p 5d 5f6s 6p 6d 6f7s 7p 7d 7f

• 1s2 2s2 2p6 3s2

3p6 4s2 3d10 4p6

5s2

• 38 electrons


1s2s 2p3s 3p 3d4s 4p 4d 4f

5s 5p 5d 5f6s 6p 6d 6f7s 7p 7d 7f

• 1s2 2s2 2p6 3s2

3p6 4s2 3d10 4p6

5s2 4d10 5p6 6s2

• 56 electrons


1s2s 2p3s 3p 3d4s 4p 4d 4f

5s 5p 5d 5f6s 6p 6d 6f7s 7p 7d 7f

• 1s2 2s2 2p6 3s2

3p6 4s2 3d10 4p6

5s2 4d10 5p6 6s2

4f14 5d10 6p6 7s2

• 88 electrons


1s2s 2p3s 3p 3d4s 4p 4d 4f

5s 5p 5d 5f6s 6p 6d 6f7s 7p 7d 7f

• 1s2 2s2 2p6 3s2

3p6 4s2 3d10 4p6

5s2 4d10 5p6 6s2

4f14 5d10 6p6 7s2

5f14 6d10 7p6 • 118 electrons

Rewrite when doneRewrite when done

Group the energy levels togetherGroup the energy levels together

• 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14

5s2 5p6 5d105f146s2 6p6 6d10 7s2 7p6

• 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10

5p6 6s2 4f14 5d10 6p6 7s2 5f14 6d10 7p6

The Modern TableThe Modern Table Elements are still grouped by propertiesElements are still grouped by properties Similar properties are in the same columnSimilar properties are in the same column Order is in increasing atomic numberOrder is in increasing atomic number Added a column of elements Mendeleev Added a column of elements Mendeleev

didn’t know about.didn’t know about. The noble gases weren’t found because The noble gases weren’t found because

they didn’t react with anything.they didn’t react with anything.

Horizontal rows are called periods or Horizontal rows are called periods or principal energy levels.principal energy levels.

There are 7 periodsThere are 7 periods

Vertical columns are called groups.Vertical columns are called groups. Elements are placed in columns by Elements are placed in columns by

similar properties.similar properties. Also called familiesAlso called families

1A

2A 3A 4A 5A 6A7A

8A0

The elements in the A groups are The elements in the A groups are called the called the representative elementsrepresentative elements

Representative ElementsRepresentative Elements Groups IA-VIIIAGroups IA-VIIIA S and p BlockS and p Block Obey the octet ruleObey the octet rule

1A 2A

3A 4A 5A 6A 7A

8A

3B 4B 5B 6B 7B 8B 8B 8B 1B 2B

1 2

13 14 15 16 17

18

3 4 5 6 7 8 9 10 11 12

IA IIA

IIIA

IVA

V A VIA

VII

A

VII

IA

IIIB

IVB

VA

VIB

VII

B

VII

IB

IB IIB

Other Systems CAS System for A and B (Chemical Abstract Service)

IUPAC System for 1-18 (International Union of Pure and Applied Chemistry)

MetalsMetals

MetalsMetals Luster – shiny.Luster – shiny. DuctileDuctile – drawn into wires. – drawn into wires. MalleableMalleable – hammered into sheets. – hammered into sheets. Conductors of heat and electricity.Conductors of heat and electricity. Why? Sea of “mobile” electrons.Why? Sea of “mobile” electrons.

Transition metalsTransition metals

The Group B The Group B elementselements

Non-metalsNon-metals DullDull BrittleBrittle NonconductorsNonconductors

- insulators- insulators

Metalloids or SemimetalsMetalloids or Semimetals

Properties of bothProperties of both SemiconductorsSemiconductors

These are called the inner transition elements and they belong here

Group 1A are the alkali metalsGroup 1A are the alkali metals Group 2A are the alkaline earth metalsGroup 2A are the alkaline earth metals

Group 7A is called the HalogensGroup 7A is called the Halogens Group 8A are the noble gasesGroup 8A are the noble gases

Why?Why? The part of the atom another atom sees The part of the atom another atom sees

is the electron cloud.is the electron cloud. More importantly the outside orbitals More importantly the outside orbitals The orbitals fill up in a regular patternThe orbitals fill up in a regular pattern The outside orbital electron configuration The outside orbital electron configuration

repeatsrepeats So.. the properties of atoms repeat.So.. the properties of atoms repeat.

1s1s11

1s1s222s2s11

1s1s222s2s222p2p663s3s11

1s1s222s2s222p2p663s3s223p3p664s4s11

1s1s222s2s222p2p663s3s223p3p663d3d10104s4s224p4p665s5s11

1s1s222s2s222p2p663s3s223p3p663d3d10104s4s224p4p664d4d10105s5s2 2 5p5p666s6s11

1s1s222s2s222p2p663s3s223p3p663d3d10104s4s224p4p664d4d10104f4f14145s5s225p5p66

5d5d10106s6s226p6p667s7s11

H1

Li3

Na11

K19

Rb37

Cs55

Fr87

He2

Ne10

Ar18

Kr36

Xe54

Rn86

11ss22

1s1s222s2s222p2p66

1s1s222s2s222p2p663s3s223p3p66

1s1s222s2s222p2p663s3s223p3p663d3d10104s4s224p4p66

1s1s222s2s222p2p663s3s223p3p663d3d10104s4s224p4p664d4d10105s5s225p5p66

1s1s222s2s222p2p663s3s223p3p663d3d10104s4s224p4p664d4d10105s5s224f4f14 14

5p5p665d5d10106s6s226p6p66

Alkali metals all end in sAlkali metals all end in s11

Alkaline earth metals all end in sAlkaline earth metals all end in s22

really have to include He but it fits really have to include He but it fits better laterbetter later

He has the properties of the noble He has the properties of the noble gasesgases

s2s1

S- blockS- block

Transition Metals -d blockTransition Metals -d block

d1 d2 d3s1 d5

d5 d6 d7 d8s1 d9

d10

The P-blockThe P-block p1 p2 p3 p4 p5 p6

F - blockF - block inner transition elementsinner transition elements

f1 f5f2 f3 f4

f6 f7 f8 f9 f10 f11 f12 f14

f13

Each row (or period) is the energy level Each row (or period) is the energy level for s and p orbitalsfor s and p orbitals

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d orbitals fill up after previous energy level so first d d orbitals fill up after previous energy level so first d is 3d even though it’s in row 4is 3d even though it’s in row 4

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3d

f orbitals start filling at 4ff orbitals start filling at 4f

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4f5f

Writing Electron Writing Electron configurations the easy wayconfigurations the easy way

Yes there is a shorthandYes there is a shorthand

Electron Configurations repeatElectron Configurations repeat The shape of the periodic table is a The shape of the periodic table is a

representation of this repetition.representation of this repetition. When we get to the end of the row the When we get to the end of the row the

outermost energy level is full.outermost energy level is full. This is the basis for our shorthandThis is the basis for our shorthand

The ShorthandThe Shorthand Write the symbol of the noble gas Write the symbol of the noble gas

before the element in brackets [ ]before the element in brackets [ ] Then the rest of the electrons.Then the rest of the electrons. Aluminum - full configurationAluminum - full configuration 1s1s222s2s222p2p663s3s223p3p11

Ne is 1sNe is 1s222s2s222p2p66

so Al is [Ne] 3sso Al is [Ne] 3s223p3p11

More examplesMore examples Ge = 1sGe = 1s222s2s222p2p663s3s223p3p663d3d10104s4s224p4p22

Ge = [Ar] 4sGe = [Ar] 4s223d3d10104p4p22

Ge = [Ar] 3dGe = [Ar] 3d10104s4s224p4p22

Hf=1sHf=1s222s2s222p2p663s3s223p3p664s4s223d3d10104p4p664f4f14 14

4d4d10105s5s225p5p665d5d226s6s22

Hf=[Xe]6sHf=[Xe]6s224f4f14145d5d22

Hf=[Xe]4fHf=[Xe]4f14145d5d226s6s22

The ShorthandThe Shorthand

Sn- 50 electrons

The noble gas before it is Kr

[ Kr ]

Takes care of 36

Next 5s2

5s2

Then 4d10

4d10Finally 5p2

5p2

Electron configurations and groupsElectron configurations and groups Representative elements have s and p Representative elements have s and p

orbitals as last filledorbitals as last filled

– Group number = number of electrons Group number = number of electrons in highest energy levelin highest energy level

Transition metals- d orbitalsTransition metals- d orbitals Inner transition- f orbitalsInner transition- f orbitals Noble gases s and p orbitals fullNoble gases s and p orbitals full

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Atomic Structure