Chapter 5 ReviewChapter 5 Review

Wave Nature of LightWave Nature of Light Wavelength- Wavelength-

The distance between two consecutive peaks The distance between two consecutive peaks or troughs.or troughs.

Frequency- Frequency- The number of waves that pass a point each The number of waves that pass a point each second (the unit is the Hertz, Hz). One second (the unit is the Hertz, Hz). One complete wave or cycle per. second = 1 Hz.complete wave or cycle per. second = 1 Hz.

Velocity-Velocity- Distance a peak moves in a unit of time.Distance a peak moves in a unit of time.

Particle Nature of LightParticle Nature of Light

PHOTOELECTRIC EFFECTPHOTOELECTRIC EFFECTWhen light shines on certain metals an When light shines on certain metals an

electric current is produced (electrons are electric current is produced (electrons are emitted from the metal).emitted from the metal).

Not explained by the wave theory of Not explained by the wave theory of light…light…

Light is thought of as a stream of particles Light is thought of as a stream of particles called…called…

Bohr’s ModelBohr’s ModelAtom absorbs energy Atom absorbs energy electron ‘jumps’ electron ‘jumps’

to a higher energy level (orbit).to a higher energy level (orbit).

Electron ‘jumps’ to a lower orbit Electron ‘jumps’ to a lower orbit energy energy released (photon).released (photon).

Energy difference between the two orbits Energy difference between the two orbits energy of the photon energy of the photon The color The color (frequency) of light produced (frequency) of light produced E = h fE = h f

Bohr’s ShortcomingsBohr’s ShortcomingsQuantized energy levels were not Quantized energy levels were not

immediately accepted by other scientists immediately accepted by other scientists (though correct)(though correct)

Worked for hydrogen but not for other Worked for hydrogen but not for other elements with more electrons.elements with more electrons.

Heisenberg Uncertainty PrincipleHeisenberg Uncertainty Principle

It is impossible to determine It is impossible to determine simultaneously the position and velocity of simultaneously the position and velocity of an electron or any other particle.an electron or any other particle.

OrbitalOrbitalA three dimensional region around the A three dimensional region around the

nucleus that indicates the most probable nucleus that indicates the most probable location of the electron.location of the electron.

Quantum NumbersQuantum NumbersDescribe the properties of atomic orbitals Describe the properties of atomic orbitals

and the electrons that occupy them…and the electrons that occupy them…Quantum NumberQuantum Number DescribesDescribesPrinciple Principle -- main E. levelmain E. levelAngular Momentum - Angular Momentum - shape of Orbitalshape of OrbitalMagnetic Magnetic -- orientation of orbitalorientation of orbitalSpinSpin -- orientation of electronorientation of electron

Rules for Writing eRules for Writing e- - configurationsconfigurations

An electron occupies the lowest energy An electron occupies the lowest energy orbital that can receive it…(like filling a orbital that can receive it…(like filling a glass)glass)

If two electrons occupy the same orbital If two electrons occupy the same orbital they must have opposite spins!they must have opposite spins!

Orbitals of equal energy are each Orbitals of equal energy are each occupied by one electron before any occupied by one electron before any orbital is occupied by a second electron.orbital is occupied by a second electron.

1S1S22 2S2S22 2P 2P22

What do the symbols What do the symbols represent?represent?

Write Orbital notation forWrite Orbital notation forNitrogenNitrogen

Electron configuration for:Electron configuration for:NeNe

1S1S22 2S2S222P2P66

Nobel Gas Notation for:Nobel Gas Notation for:AluminumAluminum

Al [Ne] 3SAl [Ne] 3S22 3P 3P11

How does the arrangement of How does the arrangement of electrons relate to an elements electrons relate to an elements position on the periodic table?position on the periodic table?

…….where would find an element with an .where would find an element with an outermost energy level like this 4Soutermost energy level like this 4S224P4P44 ? ?

Calculate Frequency and energyCalculate Frequency and energy

Wavelength = 4.5 x 10Wavelength = 4.5 x 10-7-7 meters meters

Region outside of nucleus where Region outside of nucleus where an electron can most probably an electron can most probably

be foundbe found

OrbitalOrbital

An electron in the lowest An electron in the lowest possible energy level said to be possible energy level said to be

in it’sin it’s

Ground stateGround state

When an electron absorbs When an electron absorbs energy it will be in…energy it will be in…

An excited stateAn excited state

A photon is released when an A photon is released when an electron moves from electron moves from

Excited state to ground stateExcited state to ground state

A quantum of electromagnetic A quantum of electromagnetic energy is aenergy is a

PhotonPhoton

How does an orbit differ from an How does an orbit differ from an orbital?orbital?

Orbitals do not show the exact location or Orbitals do not show the exact location or path of an electron… only the probable path of an electron… only the probable locationlocation

It is not possible to know the It is not possible to know the precise location and velocity of precise location and velocity of

an electron or other small an electron or other small particle (“what is…”)particle (“what is…”)

Heisenberg uncertainty principleHeisenberg uncertainty principle

Indicates the main energy level of Indicates the main energy level of an orbital or electronan orbital or electron

Principle quantum numberPrinciple quantum number

An electron at main energy level 5 An electron at main energy level 5 has more ___ than an electron at has more ___ than an electron at

main energy level 2main energy level 2

EnergyEnergy

Dumbell-shaped set of 3 orbitalsDumbell-shaped set of 3 orbitals

P ORBITALSP ORBITALS

Indicates the orientation of the Indicates the orientation of the orbital with regard to a three orbital with regard to a three

dimensional axisdimensional axisMagnetic quantum numberMagnetic quantum number

A spherical electron cloudA spherical electron cloudS orbitalS orbital

The difference between a 2S orbital The difference between a 2S orbital and a 3S orbitaland a 3S orbital

Distance from nucleus or energy levelDistance from nucleus or energy level

An electron occupies the lowest An electron occupies the lowest energy orbital that can receive itenergy orbital that can receive it

Aufbau principleAufbau principle

Orbitals of equal energy are each Orbitals of equal energy are each occupied by one electron before occupied by one electron before

any is occupied by a second any is occupied by a second electron.electron.

Hund’s RuleHund’s Rule

Two electrons in the same Two electrons in the same orbital must have opposite spinsorbital must have opposite spinsPauli exclusion principlePauli exclusion principle

The Bohr model was an attempt to The Bohr model was an attempt to explain what about hydrogenexplain what about hydrogen

Bright line or line emission spectrumBright line or line emission spectrum

The number of electrons in the The number of electrons in the highest occupied energy level of highest occupied energy level of

argon (a noble gas)argon (a noble gas) 88

The distance between successive The distance between successive peaks on a wave peaks on a wave

wavelengthwavelength