Chapter 5 Review

Wave Nature of Light Wavelength- Wavelength- The distance between two consecutive peaks or troughs. Frequency- Frequency- The number of waves that pass a point each second (the unit is the Hertz, Hz). One 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 Light PHOTOELECTRIC EFFECT When light shines on certain metals an electric current is produced (electrons are emitted from the metal). When light shines on certain metals an electric current is produced (electrons are emitted from the metal). Not explained by the wave theory of light… Not explained by the wave theory of light… Light is thought of as a stream of particles called… Light is thought of as a stream of particles called…

Bohr’s Model Atom absorbs energy  electron ‘jumps’ to a higher energy level (orbit). Atom absorbs energy  electron ‘jumps’ to a higher energy level (orbit). Electron ‘jumps’ to a lower orbit  energy released (photon). Electron ‘jumps’ to a lower orbit  energy released (photon). Energy difference between the two orbits  energy of the photon  The color (frequency) of light produced  E = h f Energy difference between the two orbits  energy of the photon  The color (frequency) of light produced  E = h f

Bohr’s Shortcomings Quantized energy levels were not immediately accepted by other scientists (though correct) Quantized energy levels were not immediately accepted by other scientists (though correct) Worked for hydrogen but not for other elements with more electrons. Worked for hydrogen but not for other elements with more electrons.

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

Orbital A three dimensional region around the nucleus that indicates the most probable location of the electron. A three dimensional region around the nucleus that indicates the most probable location of the electron.

Quantum Numbers Describe the properties of atomic orbitals and the electrons that occupy them… Describe the properties of atomic orbitals and the electrons that occupy them… Quantum NumberDescribes Principle -main E. level Principle -main E. level Angular Momentum - shape of Orbital Angular Momentum - shape of Orbital Magnetic -orientation of orbital Magnetic -orientation of orbital Spin-orientation of electron Spin-orientation of electron

Rules for Writing e - configurations An electron occupies the lowest energy orbital that can receive it…(like filling a glass) An electron occupies the lowest energy orbital that can receive it…(like filling a glass) If two electrons occupy the same orbital they must have opposite spins! If two electrons occupy the same orbital they must have opposite spins! Orbitals of equal energy are each occupied by one electron before any orbital is occupied by a second electron. Orbitals of equal energy are each occupied by one electron before any orbital is occupied by a second electron.

1S 2 2S 2 2P 2

What do the symbols represent?

Write Orbital notation for Nitrogen Nitrogen

Electron configuration for: Ne Ne 1S 2 2S 2 2P 6 1S 2 2S 2 2P 6

Nobel Gas Notation for: Aluminum Aluminum Al [Ne] 3S 2 3P 1 Al [Ne] 3S 2 3P 1

How does the arrangement of electrons relate to an elements position on the periodic table? ….where would find an element with an outermost energy level like this 4S 2 4P 4 ? ….where would find an element with an outermost energy level like this 4S 2 4P 4 ?

Calculate Frequency and energy Wavelength = 4.5 x meters Wavelength = 4.5 x meters

Region outside of nucleus where an electron can most probably be found Orbital Orbital

An electron in the lowest possible energy level said to be in it’s Ground state Ground state

When an electron absorbs energy it will be in… An excited state An excited state

A photon is released when an electron moves from Excited state to ground state Excited state to ground state

A quantum of electromagnetic energy is a Photon Photon

How does an orbit differ from an orbital? Orbitals do not show the exact location or path of an electron… only the probable location Orbitals do not show the exact location or path of an electron… only the probable location

It is not possible to know the precise location and velocity of an electron or other small particle (“what is…”) Heisenberg uncertainty principle Heisenberg uncertainty principle

Indicates the main energy level of an orbital or electron Principle quantum number Principle quantum number

An electron at main energy level 5 has more ___ than an electron at main energy level 2 Energy Energy

Dumbell-shaped set of 3 orbitals P ORBITALS P ORBITALS

Indicates the orientation of the orbital with regard to a three dimensional axis Magnetic quantum number Magnetic quantum number

A spherical electron cloud S orbital S orbital

The difference between a 2S orbital and a 3S orbital Distance from nucleus or energy level Distance from nucleus or energy level

An electron occupies the lowest energy orbital that can receive it Aufbau principle Aufbau principle

Orbitals of equal energy are each occupied by one electron before any is occupied by a second electron. Hund’s Rule Hund’s Rule

Two electrons in the same orbital must have opposite spins Pauli exclusion principle Pauli exclusion principle

The Bohr model was an attempt to explain what about hydrogen Bright line or line emission spectrum Bright line or line emission spectrum

The number of electrons in the highest occupied energy level of argon (a noble gas) 8 8

The distance between successive peaks on a wave wavelength wavelength