DrillDrill

Determine the electron Determine the electron configuration of the following:configuration of the following: HH HeHe

ObjectiveObjective

SWBAT: SWBAT: Use a flame test in order to determine Use a flame test in order to determine

the identity of the cation in an unknown the identity of the cation in an unknown solution based on its characteristic solution based on its characteristic color in a flame.color in a flame.

SAT/HSA EnrichmentSAT/HSA Enrichment

……has a mass that is approximately has a mass that is approximately the same as the mass of …the same as the mass of …

a.a. a beta article…a protona beta article…a proton

b.b. a neutron…a protona neutron…a proton

c.c. an alpha particle…an electronan alpha particle…an electron

d.d. a positron….an electrona positron….an electron

e.e. an electron…a neutronan electron…a neutron

Engagement:Engagement:

Things to think about during today’s activity. Atoms of different elements have

distinct properties related to their composition.

How do atoms of different elements differ?

PhysicsPhysics

How do atoms relate?How do atoms relate?

Physics and the Quantum Physics and the Quantum Mechanical ModelMechanical Model

• Neon advertising signs are Neon advertising signs are formed from glass tubes formed from glass tubes bent in various shapes. An bent in various shapes. An electric current passing electric current passing through the gas in each through the gas in each glass tube makes the gas glass tube makes the gas glow with its own glow with its own characteristic color. You characteristic color. You will learn why each gas will learn why each gas glows with a specific color glows with a specific color of light.of light.

LightLight The The amplitudeamplitude of a wave is the of a wave is the wave’s wave’s

height from zero to the crest. height from zero to the crest. The The wavelengthwavelength, represented by , represented by (the (the

Greek letter lambda), is the Greek letter lambda), is the distance distance between the crestsbetween the crests. .

The The frequencyfrequency, represented by , represented by (the (the Greek letter nu), is the Greek letter nu), is the number of wave number of wave cycles to pass a given point per unit of cycles to pass a given point per unit of time. time. The SI unit of The SI unit of cycles per secondcycles per second is called a is called a

hertzhertz (Hz). (Hz).

LightLight

The The wavelengthwavelength and and frequencyfrequency of of lightlight are are inversely proportionalinversely proportional to each other.to each other.

LightLight

The The productproduct of the of the frequencyfrequency and and wavelengthwavelength always equals a constant always equals a constant ((cc), the speed of light.), the speed of light.

LightLight

According to the wave model, light According to the wave model, light consists of electromagnetic waves.consists of electromagnetic waves. Electromagnetic radiationElectromagnetic radiation includes includes

radio waves, microwaves, infrared radio waves, microwaves, infrared waves, visible light, ultraviolet waves, waves, visible light, ultraviolet waves, X-rays, and gamma rays. X-rays, and gamma rays.

All electromagnetic waves All electromagnetic waves travel in a travel in a vacuumvacuum at a at a speed speed of of 2.998 2.998 10 108 8 m/s.m/s.

LightLight

Sunlight consists of light with a Sunlight consists of light with a continuous range of wavelengths continuous range of wavelengths and frequencies. and frequencies. When When sunlight passes through a prism, sunlight passes through a prism,

the different frequencies separatethe different frequencies separate into a into a spectrumspectrum of of colorscolors..

In the In the visible spectrum, red light has visible spectrum, red light has the longest wavelength and the lowest the longest wavelength and the lowest frequency.frequency.

LightLight

The electromagnetic spectrum The electromagnetic spectrum consists of radiation over a broad consists of radiation over a broad band of wavelengths.band of wavelengths.

Atomic SpectraAtomic Spectra

When When atoms absorb energyatoms absorb energy, , electrons move into higher energy electrons move into higher energy levels. levels. These These electrons then lose energyelectrons then lose energy by by

emitting lightemitting light when they return to when they return to lower lower energy levelsenergy levels..

Atomic SpectraAtomic Spectra A prism separates light into the colors it A prism separates light into the colors it

contains. When white light passes contains. When white light passes through a prism, it produces a rainbow through a prism, it produces a rainbow of colors.of colors.

Atomic SpectraAtomic Spectra

When light from a helium lamp When light from a helium lamp passes through a prism, discrete passes through a prism, discrete lines are produced.lines are produced.

Atomic SpectraAtomic Spectra The The frequencies of light emittedfrequencies of light emitted by by

an an element separate into discrete element separate into discrete lineslines to give the to give the atomic emission atomic emission spectrumspectrum of the element. of the element.

Mercury Nitrogen

An Explanation of Atomic An Explanation of Atomic SpectraSpectra

In the Bohr model, the lone electron in the In the Bohr model, the lone electron in the hydrogen atom can have only certain hydrogen atom can have only certain specific energies.specific energies. When the When the electron has its lowest possible electron has its lowest possible

energyenergy, the atom is in its , the atom is in its ground stateground state.. Excitation of the electronExcitation of the electron by by absorbing absorbing

energy raisesenergy raises the the atom from the ground state atom from the ground state to an excited stateto an excited state..

A A quantum of energyquantum of energy in the form of in the form of light is light is emittedemitted when the when the electron drops back to a electron drops back to a lower energy level.lower energy level.

An Explanation of Atomic An Explanation of Atomic SpectraSpectra

The The light emitted by an electron light emitted by an electron moving from a higher to a lower moving from a higher to a lower energy level has a frequency directly energy level has a frequency directly proportional to the energy change of proportional to the energy change of the electron.the electron.

An Explanation of Atomic An Explanation of Atomic SpectraSpectra

The three groups of lines in the The three groups of lines in the hydrogen spectrum correspond to hydrogen spectrum correspond to the transition of electrons from the transition of electrons from higher energy levels to lower energy higher energy levels to lower energy levels. levels.

Quantum MechanicsQuantum Mechanics

In 1905, Albert Einstein successfully In 1905, Albert Einstein successfully explained experimental data by explained experimental data by proposing that light could be proposing that light could be described as quanta of energy.described as quanta of energy. The quanta behave as if they were The quanta behave as if they were

particles.particles. Light quantaLight quanta are called are called photonsphotons..

In 1924, De Broglie developed an In 1924, De Broglie developed an equation that predicts that all moving equation that predicts that all moving objects have wavelike behavior. objects have wavelike behavior.

Quantum MechanicsQuantum Mechanics

Today, the wavelike properties of Today, the wavelike properties of beams of electrons are useful in beams of electrons are useful in magnifying objects. The electrons in an magnifying objects. The electrons in an electron microscope have much smaller electron microscope have much smaller wavelengths than visible light. This wavelengths than visible light. This allows a much clearer enlarged image allows a much clearer enlarged image of a very small object, such as this mite.of a very small object, such as this mite.

Quantum MechanicsQuantum Mechanics

Classical mechanics adequately Classical mechanics adequately describes the motions of bodies much describes the motions of bodies much larger than atoms, while quantum larger than atoms, while quantum mechanics describes the motions of mechanics describes the motions of subatomic particles and atoms as subatomic particles and atoms as waves.waves.

Quantum MechanicsQuantum Mechanics

The The Heisenberg uncertainty Heisenberg uncertainty principleprinciple states that it is states that it is impossible impossible to know exactly both the velocity and to know exactly both the velocity and the position of a particle at the same the position of a particle at the same time.time. This limitation is critical in This limitation is critical in dealing with dealing with

small particles such as electrons. small particles such as electrons. This limitation does not matter for This limitation does not matter for

ordinary-sized object such as cars or ordinary-sized object such as cars or airplanes.airplanes.

Quantum MechanicsQuantum Mechanics The Heisenberg Uncertainty PrincipleThe Heisenberg Uncertainty Principle

Quick Quiz.Quick Quiz.1.1. The lines in the emission spectrum for The lines in the emission spectrum for

an element are caused by an element are caused by a.a. the movement of electrons from lower to the movement of electrons from lower to

higher energy levels.higher energy levels.

b.b. the movement of electrons from higher to the movement of electrons from higher to lower energy levels.lower energy levels.

c.c. the electron configuration in the ground the electron configuration in the ground state.state.

d.d. the electron configuration of an atom.the electron configuration of an atom.

Quick QuizQuick Quiz2.Spectral lines in a series become closer 2.Spectral lines in a series become closer

together as n increases because the together as n increases because the a.a. energy levels have similar values.energy levels have similar values.

b.b. energy levels become farther apart.energy levels become farther apart.

c.c. atom is approaching ground state.atom is approaching ground state.

d.d. electrons are being emitted at a slower electrons are being emitted at a slower rate.rate.

Spectrum ParkSpectrum Park

Letter from Mrs. LatticeLetter from Mrs. Lattice Teacher Flame test DemoTeacher Flame test Demo Complete Flame test Lab and Complete Flame test Lab and

Analysis Questions.Analysis Questions.

Summary QuestionsSummary Questions

Was the objective accomplished? Explain. How do atoms of different elements

differ? Identify the main concepts of today’s

activity. How does your lab investigation relate to

the activity of electrons? Use the following: Ground state – lowest energy level Excited state – higher energy level

HomeworkHomework

Letter to Ms. LatticeLetter to Ms. Lattice