EXPERIMENT 13. Balmer Series of Hydrogen

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "EXPERIMENT 13. Balmer Series of Hydrogen"

Transcription

1 EXPERIMENT 13 Balmer Series of Hydrogen Any atomic gas or element (heated to vapor form) can be made to radiate light when suitably "excited" by an electric discharge, spark, or flame. If this light is viewed through a prism or diffraction grating, the spectrum consists of a series of discrete lines whose wavelengths are characteristic of the element concerned. The wavelengths that occur are directly related to the structure of the atom; in fact, our modern theory of atomic structure developed as a result of attempts to explain observed spectra. The purpose of this experiment is to gain insight into the structure of the simplest atom by analyzing the wavelength of the Balmer series of hydrogen. The results are then correlated to Bohr's theory of the hydrogen atom. Theory In 1885 J.J. Balmer succeeded in fitting a mathematical equation to the visible wavelengths of hydrogen, namely 1 1 = R 4 1 n 2 n = 3,4,5... (1) where R was an experimentally determined constant, called the Rydberg constant. The values of n corresponded to successive lines of the so-called Balmer series as shown in figure (1), where the symbols H, H, H, etc. are the traditional names given to the lines. series limit n=8 n=7 n=6 n=5 n=4 n=3 H ξ H ε H δ H γ H β H α Ultraviolet Violet Blue Blue-Green red Figure 1 The Balmer series of spectral lines for hydrogen. The wavelengths λ are given in nanometers. Although Balmer's equation accurately predicted the wavelengths, no one understood why. It was not until 1913 that Neils Bohr applied quantum ideas to develop a theory, which successfully explained the origin of the lines and showed how Balmer's equation could be derived theoretically. Bohr postulated that the electron, orbiting around

2 13-2 the nucleus, could only do so in certain discrete orbits. The energy E of the atom when the electron is in a stationary orbit with quantum number n is given by E = me4 Z 2 8εo 2 h 2 n 2 n = 1,2,3... (2) where m is the mass of the electron, e is the electronic charge, h is Planck's constant, is the permittivity of free space, Z is the atomic number of the atom. The energies specified by equation (2) can be represented by an energy-level diagram as shown in figure (2) where E 1 is the ground state of the electron and, E 2, E 3, E 4, etc. indicated excited states. Bohr showed that the observed spectral lines were caused by electrons making transitions from one energy level to another. He stated that if an electron in an initial energy state E i drops to a final lower state E f, the energy difference E = E i E f is radiated as a photon whose energy is given by Einstein's equation E = hf. Substituting equation (2) into E i - E f = h(c / ), Bohr obtained the following expression for the wavelength of the emitted radiation: o 1 λ = Z 2 4 me 8ε o 2 h 3 c 1 n 2-1 f n 2 i (3) n= E = 0 n=5 n=4 n=3 E E 5 4 E 3 This theoretical expression corresponds exactly to the form of Balmer's empirical equation if Z = 1 and n f = 2. The numerical value of the quantity n=2 H H H H 123 Balmer series E 2 me 4 8ε o 2 h 3 c agrees very closely with the experimental value of R. However, even better agreement can be obtained if the electron mass m in equation (3) is replaced by the "reduced mass" m* given by n=1 ground state E 1 Figure 2 Energy level diagram for the Balmer series of hydrogen. m* = mm (m + M) (4)

3 13-3 where M is the mass of the nucleus. This correction is necessary to account for the fact that the nucleus is not stationary but that both the nucleus and electron revolve about their common center of mass. Using the reduced mass m*, equation (3) can be rewritten as 1 / = Z 2 R(1 / n f 2 1 / n i 2 ) where the appropriate expression for R becomes: R = M m +M R R =- me 4 8ε o 2 h 3 c (5) The quantity R is simply a notation representing the value of R when M/m. For the case of hydrogen, the ratio M/m is about 1836, so that the value of R Hydrogen is slightly smaller than R. Today, the best available value of R is x 10 7 m -1. As a final note, Bohr predicted the existence of other series in the hydrogen spectrum by substituting different values of n f in equation (3). These series, which were all later confirmed experimentally, are: Lyman series (n f = 1), Paschen series (n f = 3), Brackett series (n f = 4), and Pfund series (n f = 5). Furthermore, Bohr's theory for the hydrogen atom also works for other single-electron systems such as He +, Li ++, etc. each of which have a slightly different Rydberg constant. The downfall of the Bohr theory came when it could not give the correct energies for more complex atoms and this is where the need for modern quantum mechanics arose. Grating Spectrometer spectrometer table φ R slit θ R φ 0 (center) light source collimator θ L grating mount eyepiece telescope Figure 3 A schematic diagram of a grating spectrometer used to measure wavelengths of the light source.

4 13-4 In this experiment, a spectrometer mounted with a diffraction grating is used to measure the wavelengths of light (see figure 3). The spectrometer consists of a collimator which allows parallel light rays to pass through the grating, a telescope to view the resultant spectrum, and a rotatable table. If care is taken to ensure that the light enters the grating with normal incidence, the wavelength of a spectral line is given by the familiar relation mλ = d sinθ m = 0,1,2,3,.. (6) where d is the spacing of the "slits" in the grating, m is the order of the diffracted wavelength, and is the angle through which the wavelength has been deviated. A schematic diagram showing the arrangement for the first three orders of the hydrogen spectrum is illustrated in figure (1) below. m=2 m=1 Left m=0 m=1 Right m=2 Figure 4 Representation of 3 successive orders for the hydrogen spectrum. The theory of the diffraction grating is available in most texts for those who are not familiar with it. Procedure: Part I: Spectrometer Alignment When using the spectrometer, wear your glasses or contacts if you normally do so. In order that the spectrometer is properly set for use with this experiment, the following adjustments are necessary: 1. Focus the eyepiece so that the cross-hairs are clearly visible. 2. Focus the telescope for parallel light by viewing a distant object and obtain a clear image with no parallax relative to the cross-hairs. Parallax occurs if the image appears to move when you gently bob your head from side to side while sighting into the telescope. Note: Once the telescope has been set for parallel light, it should not be re-adjusted during the rest of the experiment.

5 Turn on the hydrogen lamp for about 5 minutes, and place it as close as possible to the entrance slit of the collimator. Line up the collimator slit and telescope cross hairs. This is done by centering the cross hairs on the image of the slit in the telescope. Adjust the collimator so that a sharp image of the slit is seen when sighting through the telescope. This is the zeroth order diffraction line. The accuracy of the spectrometer is limited by the size of the collimator slit and by the angular sensitivity of the spectrometer table. A narrow slit is necessary for precise measurements but it may give too faint an image. A slightly wider slit can be used and then narrowed prior to the final reading. Part II: Grating Alignment 1. Carefully mount the grating in the holder and rotate the spectrometer table so that the slide is perpendicular to the collimator axis. 2. To verify that the grating is perpendicular to the collimator axis first, measure the position of the zeroth order diffraction line 0 (m=0). Next rotate the telescope to the left and locate the first order red spectral line. Depending on the diffraction grating this rotation will be 15 to 20 degrees from the central (m=0) bright line. Record the angular position of the line L. Next record the angular position of the first order red line to the right of the central line R. Finally check that the diffracted angles to the left and right are equal within 0.1. If they are not equal then rotate the grating until they are equal within 0.1. Once the grating is aligned, tighten the table-clamp allowing the telescope to rotate freely. 3. If the spectral lines appear too faint, first adjust the lamp position and then, if necessary, increase the slit-size slightly using the thumb screw at the end of the collimator. If you have difficulty seeing 2 violet lines in hydrogen, check the alignment of the light source so that the spectral lines are of maximum brightness. Also blocking stray light or covering the spectrometer arrangement with a dark cloth is helpful. Part III: Hydrogen Spectrum measurements 1. Record the position for the zeroth order diffraction line 0 (m=0). 2. Locate as many of the first order spectral lines as possible to the left of the central line. Center the cross hairs of the telescope on each line and record the position calculate the corresponding diffracted angle., then 3. Repeat the measurements using the first order spectral lines located to the right of the central line.

6 13-6 Analysis 1. Using equation (6), calculate the wavelength λ ± δλ for one set of spectral lines Graph vs n Find the value for R and its uncertainty from the slope of the resulting graph. 4. Repeat steps (1) to (3) above using the second set of data. Questions: 1. What is the shortest wavelength in the Balmer series? Is it visible? 2. What is happening to the electron relative to the nucleus when E = 0? E > 0? E < 0? Refer to figure (2). 3. Bohr's theory helped in the discovery of the isotope deuterium, 2 H, by predicting a very small difference between the wavelengths of ordinary hydrogen and deuterium. How far apart should the H α line of these two kinds of hydrogen be? 4. If light incident on the grating makes an angle with respect to the normal to the grating, show that equation (6) becomes d[sin(θ ϕ) + sin ϕ] = mλ. 5. Derive equation (4) for m*. (Hint: The total angular momentum Iω = m*r 2 ω equals the sum of the individual angular momenta, where r = r e + r n ; r e, r n are the distances of the electron and nucleus respectively, from the center of mass.)

THE BOHR QUANTUM MODEL

THE BOHR QUANTUM MODEL THE BOHR QUANTUM MODEL INTRODUCTION When light from a low-pressure gas is subject to an electric discharge, a discrete line spectrum is emitted. When light from such a low-pressure gas is examined with

More information

WAVELENGTH OF LIGHT - DIFFRACTION GRATING

WAVELENGTH OF LIGHT - DIFFRACTION GRATING PURPOSE In this experiment we will use the diffraction grating and the spectrometer to measure wavelengths in the mercury spectrum. THEORY A diffraction grating is essentially a series of parallel equidistant

More information

GRID AND PRISM SPECTROMETERS

GRID AND PRISM SPECTROMETERS FYSA230/2 GRID AND PRISM SPECTROMETERS 1. Introduction Electromagnetic radiation (e.g. visible light) experiences reflection, refraction, interference and diffraction phenomena when entering and passing

More information

ATOMIC SPECTRA. Apparatus: Optical spectrometer, spectral tubes, power supply, incandescent lamp, bottles of dyed water, elevating jack or block.

ATOMIC SPECTRA. Apparatus: Optical spectrometer, spectral tubes, power supply, incandescent lamp, bottles of dyed water, elevating jack or block. 1 ATOMIC SPECTRA Objective: To measure the wavelengths of visible light emitted by atomic hydrogen and verify the measured wavelengths against those predicted by quantum theory. To identify an unknown

More information

Experiment #12: The Bohr Atom. Equipment: Spectroscope Hydrogen and Helium Gas Discharge Tubes, Holder, and Variac Flashlight

Experiment #12: The Bohr Atom. Equipment: Spectroscope Hydrogen and Helium Gas Discharge Tubes, Holder, and Variac Flashlight Experiment #12: The Bohr Atom Purpose: To observe the visible spectrum of hydrogen and helium and verify the Bohr model of the hydrogen atom. Equipment: Spectroscope Hydrogen and Helium Gas Discharge Tubes,

More information

5.111 Principles of Chemical Science

5.111 Principles of Chemical Science MIT OpenCourseWare http://ocw.mit.edu 5.111 Principles of Chemical Science Fall 2008 For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms. 5.111 Lecture Summary

More information

O6: The Diffraction Grating Spectrometer

O6: The Diffraction Grating Spectrometer 2B30: PRACTICAL ASTROPHYSICS FORMAL REPORT: O6: The Diffraction Grating Spectrometer Adam Hill Lab partner: G. Evans Tutor: Dr. Peter Storey 1 Abstract The calibration of a diffraction grating spectrometer

More information

Emission Spectra of Elements

Emission Spectra of Elements Fall 2003 Emission Spectra of Elements Purpose: To compare and contrast the emission spectra of various gases. Investigate quantitatively the emission spectrum of hydrogen and relate it to Bohr's theory

More information

Review of the isotope effect in the hydrogen spectrum

Review of the isotope effect in the hydrogen spectrum Review of the isotope effect in the hydrogen spectrum 1 Balmer and Rydberg Formulas By the middle of the 19th century it was well established that atoms emitted light at discrete wavelengths. This is in

More information

Light and Spectra. COLOR λ, nm COLOR λ, nm violet 405 yellow 579 blue 436 orange 623 green 492 red 689

Light and Spectra. COLOR λ, nm COLOR λ, nm violet 405 yellow 579 blue 436 orange 623 green 492 red 689 Light and Spectra INTRODUCTION Light and color have intrigued humans since antiquity. In this experiment, you will consider several aspects of light including: a. The visible spectrum of colors (red to

More information

Bohr s Model and Emission Spectra of Hydrogen and Helium

Bohr s Model and Emission Spectra of Hydrogen and Helium PHYS-01 LAB-03 Bohr s Model and Emission Spectra of Hydrogen and Helium 1. Objective The objective of this experiment is to study the emission spectrum of hydrogen and to understand its origin in terms

More information

Chapter 7: The Quantum-Mechanical Model of the Atom

Chapter 7: The Quantum-Mechanical Model of the Atom C h e m i s t r y 1 A : C h a p t e r 7 P a g e 1 Chapter 7: The Quantum-Mechanical Model of the Atom Homework: Read Chapter 7. Work out sample/practice exercises Suggested Chapter 7 Problems: 37, 39,

More information

Atoms Absorb & Emit Light

Atoms Absorb & Emit Light Atoms Absorb & Emit Light Spectra The wavelength of the light that an element emits or absorbs is its fingerprint. Atoms emit and absorb light First Test is Thurs, Feb 1 st About 30 multiple choice questions

More information

Light as a Wave. The Nature of Light. EM Radiation Spectrum. EM Radiation Spectrum. Electromagnetic Radiation

Light as a Wave. The Nature of Light. EM Radiation Spectrum. EM Radiation Spectrum. Electromagnetic Radiation The Nature of Light Light and other forms of radiation carry information to us from distance astronomical objects Visible light is a subset of a huge spectrum of electromagnetic radiation Maxwell pioneered

More information

TIME OF COMPLETION NAME SOLUTION DEPARTMENT OF NATURAL SCIENCES. PHYS 3650, Exam 2 Section 1 Version 1 October 31, 2005 Total Weight: 100 points

TIME OF COMPLETION NAME SOLUTION DEPARTMENT OF NATURAL SCIENCES. PHYS 3650, Exam 2 Section 1 Version 1 October 31, 2005 Total Weight: 100 points TIME OF COMPLETION NAME SOLUTION DEPARTMENT OF NATURAL SCIENCES PHYS 3650, Exam 2 Section 1 Version 1 October 31, 2005 Total Weight: 100 points 1. Check your examination for completeness prior to starting.

More information

PRACTICE EXAM IV P202 SPRING 2004

PRACTICE EXAM IV P202 SPRING 2004 PRACTICE EXAM IV P202 SPRING 2004 1. In two separate double slit experiments, an interference pattern is observed on a screen. In the first experiment, violet light (λ = 754 nm) is used and a second-order

More information

STUDENT SPECTROMETER. Instruction Manual and Experiment Guide for the PASCO scientific Model SP-9268A. Copyright January 1991 $7.50 012-02135F 10/03

STUDENT SPECTROMETER. Instruction Manual and Experiment Guide for the PASCO scientific Model SP-9268A. Copyright January 1991 $7.50 012-02135F 10/03 Instruction Manual and Experiment Guide for the PASCO scientific Model SP-9268A 012-02135F 10/03 STUDENT SPECTROMETER Copyright January 1991 $7.50 10101 Foothills Blvd. P.O. Box 619011 Roseville, CA 95678-9011

More information

Light, Light Bulbs and the Electromagnetic Spectrum

Light, Light Bulbs and the Electromagnetic Spectrum Light, Light Bulbs and the Electromagnetic Spectrum Spectrum The different wavelengths of electromagnetic waves present in visible light correspond to what we see as different colours. Electromagnetic

More information

Name Date Class ELECTRONS IN ATOMS. Standard Curriculum Core content Extension topics

Name Date Class ELECTRONS IN ATOMS. Standard Curriculum Core content Extension topics 13 ELECTRONS IN ATOMS Conceptual Curriculum Concrete concepts More abstract concepts or math/problem-solving Standard Curriculum Core content Extension topics Honors Curriculum Core honors content Options

More information

Answer: b. Answer: a. Answer: d

Answer: b. Answer: a. Answer: d Practice Test IV Name 1) In a single slit diffraction experiment, the width of the slit is 3.1 10-5 m and the distance from the slit to the screen is 2.2 m. If the beam of light of wavelength 600 nm passes

More information

Introduction to spectroscopy

Introduction to spectroscopy Introduction to spectroscopy How do we know what the stars or the Sun are made of? The light of celestial objects contains much information hidden in its detailed color structure. In this lab we will separate

More information

Electron Energy and Light

Electron Energy and Light Why? Electron Energy and Light How does light reveal the behavior of electrons in an atom? From fireworks to stars, the color of light is useful in finding out what s in matter. The emission of light by

More information

nm cm meters VISIBLE UVB UVA Near IR 200 300 400 500 600 700 800 900 nm

nm cm meters VISIBLE UVB UVA Near IR 200 300 400 500 600 700 800 900 nm Unit 5 Chapter 13 Electrons in the Atom Electrons in the Atom (Chapter 13) & The Periodic Table/Trends (Chapter 14) Niels Bohr s Model Recall the Evolution of the Atom He had a question: Why don t the

More information

AP CHEMISTRY CHAPTER REVIEW CHAPTER 6: ELECTRONIC STRUCTURE AND THE PERIODIC TABLE

AP CHEMISTRY CHAPTER REVIEW CHAPTER 6: ELECTRONIC STRUCTURE AND THE PERIODIC TABLE AP CHEMISTRY CHAPTER REVIEW CHAPTER 6: ELECTRONIC STRUCTURE AND THE PERIODIC TABLE You should be familiar with the wavelike properties of light: frequency ( ), wavelength ( ), and energy (E) as well as

More information

Photons. ConcepTest 27.1. 1) red light 2) yellow light 3) green light 4) blue light 5) all have the same energy. Which has more energy, a photon of:

Photons. ConcepTest 27.1. 1) red light 2) yellow light 3) green light 4) blue light 5) all have the same energy. Which has more energy, a photon of: ConcepTest 27.1 Photons Which has more energy, a photon of: 1) red light 2) yellow light 3) green light 4) blue light 5) all have the same energy 400 nm 500 nm 600 nm 700 nm ConcepTest 27.1 Photons Which

More information

Emission of Light & Atomic Models 1

Emission of Light & Atomic Models 1 Emission of Light & Atomic Models 1 Objective At the end of this activity you should be able to: o Explain what photons are, and be able to calculate their energies given either their frequency or wavelength.

More information

Bohr's Theory of the Hydrogen Atom

Bohr's Theory of the Hydrogen Atom OpenStax-CNX module: m42596 1 Bohr's Theory of the Hydrogen Atom OpenStax College This work is produced by OpenStax-CNX and licensed under the Creative Commons Attribution License 4.0 Abstract Describe

More information

2. Atomic Structure. 2.1 Historical Development of Atomic Theory. Remember!? Dmitri I. Mendeleev s Periodic Table (17 Feb. 1869 )

2. Atomic Structure. 2.1 Historical Development of Atomic Theory. Remember!? Dmitri I. Mendeleev s Periodic Table (17 Feb. 1869 ) 2. Atomic Structure 2.1 Historical Development of Atomic Theory Remember!? Dmitri I. Mendeleev s Periodic Table (17 Feb. 1869 ) 1 2.1.1 The Periodic Table of the Elements 2.1.2 Discovery of Subatomic Particles

More information

SPECTROPHOTOMETRY. Blue. Orange

SPECTROPHOTOMETRY. Blue. Orange Appendix I FV /26/5 SPECTROPHOTOMETRY Spectrophotometry is an analytical technique used to measure the amount of light of a particular wavelength absorbed by a sample in solution. This measurement is then

More information

ILLUSTRATIVE EXAMPLE: Given: A = 3 and B = 4 if we now want the value of C=? C = 3 + 4 = 9 + 16 = 25 or 2

ILLUSTRATIVE EXAMPLE: Given: A = 3 and B = 4 if we now want the value of C=? C = 3 + 4 = 9 + 16 = 25 or 2 Forensic Spectral Anaylysis: Warm up! The study of triangles has been done since ancient times. Many of the early discoveries about triangles are still used today. We will only be concerned with the "right

More information

The Nature of Electromagnetic Radiation

The Nature of Electromagnetic Radiation II The Nature of Electromagnetic Radiation The Sun s energy has traveled across space as electromagnetic radiation, and that is the form in which it arrives on Earth. It is this radiation that determines

More information

AP Chemistry A. Allan Chapter 7 Notes - Atomic Structure and Periodicity

AP Chemistry A. Allan Chapter 7 Notes - Atomic Structure and Periodicity AP Chemistry A. Allan Chapter 7 Notes - Atomic Structure and Periodicity 7.1 Electromagnetic Radiation A. Types of EM Radiation (wavelengths in meters) 10-1 10-10 10-8 4 to 7x10-7 10-4 10-1 10 10 4 gamma

More information

Chapter 18: The Structure of the Atom

Chapter 18: The Structure of the Atom Chapter 18: The Structure of the Atom 1. For most elements, an atom has A. no neutrons in the nucleus. B. more protons than electrons. C. less neutrons than electrons. D. just as many electrons as protons.

More information

Astro 130, Fall 2011, Homework, Chapter 17, Due Sep 29, 2011 Name: Date:

Astro 130, Fall 2011, Homework, Chapter 17, Due Sep 29, 2011 Name: Date: Astro 130, Fall 2011, Homework, Chapter 17, Due Sep 29, 2011 Name: Date: 1. If stellar parallax can be measured to a precision of about 0.01 arcsec using telescopes on Earth to observe stars, to what distance

More information

Chapter 6 Electromagnetic Radiation and the Electronic Structure of the Atom

Chapter 6 Electromagnetic Radiation and the Electronic Structure of the Atom Chapter 6 In This Chapter Physical and chemical properties of compounds are influenced by the structure of the molecules that they consist of. Chemical structure depends, in turn, on how electrons are

More information

Light is a type of electromagnetic (EM) radiation, and light has energy. Many kinds of light exist. Ultraviolet (UV) light causes skin to tan or burn.

Light is a type of electromagnetic (EM) radiation, and light has energy. Many kinds of light exist. Ultraviolet (UV) light causes skin to tan or burn. Light and radiation Light is a type of electromagnetic (EM) radiation, and light has energy. Many kinds of light exist. Ultraviolet (UV) light causes skin to tan or burn. Infrared (IR) light is used in

More information

Experiment IV: Atomic Spectra and the Bohr model

Experiment IV: Atomic Spectra and the Bohr model P19: INTRODUCTORY PHYSICS III Experiment IV: Atomic Spectra and the Bohr model Department of Physics and Astronomy Dartmouth College 6127 Wilder Laboratory Hanover, NH 03755 USA Overview In this lab, we

More information

Energy (J) -8E-19 -1.2E-18 -1.6E-18 -2E-18

Energy (J) -8E-19 -1.2E-18 -1.6E-18 -2E-18 Spectrophotometry Reading assignment:. http://en.wikipedia.org/wiki/beer-lambert_law Goals We will study the spectral properties of a transition metal-containing compound. We will also study the relationship

More information

Spectrum of the Hydrogen Atom

Spectrum of the Hydrogen Atom Chapter 5. Hydrogen Atom Spectrum 29 5 Spectrum of the Hydrogen Atom Objective To calculate the Rydberg constant from the spectrum of atomic hydrogen. Preparation Overview 1. Read all of this write-up.

More information

Building your own Spectroscope

Building your own Spectroscope Building your own Spectroscope 0-0.341-0.445-0.606-0.872-1.36 Lyman Balmer Paschen n=4 n=8 n=7 n=6 n=5 n=4 ENERGY/10-19 J -2.42-5.45 E 5 2 E 4 2 E 3 2 E E 5 3 4 3 n=3 n=2 (Many other transitions beyond

More information

Chemistry 2 Chapter 13: Electrons in Atoms Please do not write on the test Use an answer sheet! 1 point/problem 45 points total

Chemistry 2 Chapter 13: Electrons in Atoms Please do not write on the test Use an answer sheet! 1 point/problem 45 points total Chemistry 2 Chapter 13: Electrons in Atoms Please do not write on the test Use an answer sheet! 1 point/problem 45 points total 1. Calculate the energy in joules of a photon of red light that has a frequency

More information

5. The Nature of Light. Does Light Travel Infinitely Fast? EMR Travels At Finite Speed. EMR: Electric & Magnetic Waves

5. The Nature of Light. Does Light Travel Infinitely Fast? EMR Travels At Finite Speed. EMR: Electric & Magnetic Waves 5. The Nature of Light Light travels in vacuum at 3.0. 10 8 m/s Light is one form of electromagnetic radiation Continuous radiation: Based on temperature Wien s Law & the Stefan-Boltzmann Law Light has

More information

MODULE P7: FURTHER PHYSICS OBSERVING THE UNIVERSE OVERVIEW

MODULE P7: FURTHER PHYSICS OBSERVING THE UNIVERSE OVERVIEW OVERVIEW More than ever before, Physics in the Twenty First Century has become an example of international cooperation, particularly in the areas of astronomy and cosmology. Astronomers work in a number

More information

LAUE DIFFRACTION INTRODUCTION CHARACTERISTICS X RAYS BREMSSTRAHLUNG

LAUE DIFFRACTION INTRODUCTION CHARACTERISTICS X RAYS BREMSSTRAHLUNG LAUE DIFFRACTION INTRODUCTION X-rays are electromagnetic radiations that originate outside the nucleus. There are two major processes for X-ray production which are quite different and which lead to different

More information

Chapter 7. Quantum Theory and Atomic Structure

Chapter 7. Quantum Theory and Atomic Structure Chapter 7. Quantum Theory and Atomic Structure A problem arose in Rutherford s nuclear model. A nucleus and electron attract each other; to remain apart the electron must move. The energy of the electron

More information

WAVES AND ELECTROMAGNETIC RADIATION

WAVES AND ELECTROMAGNETIC RADIATION WAVES AND ELECTROMAGNETIC RADIATION All waves are characterized by their wavelength, frequency and speed. Wavelength (lambda, ): the distance between any 2 successive crests or troughs. Frequency (nu,):

More information

Flame Tests & Electron Configuration

Flame Tests & Electron Configuration Flame Tests & Electron Configuration INTRODUCTION Many elements produce colors in the flame when heated. The origin of this phenomenon lies in the arrangement, or configuration of the electrons in the

More information

PHYSICS PAPER 1 (THEORY)

PHYSICS PAPER 1 (THEORY) PHYSICS PAPER 1 (THEORY) (Three hours) (Candidates are allowed additional 15 minutes for only reading the paper. They must NOT start writing during this time.) ---------------------------------------------------------------------------------------------------------------------

More information

The Early History of Quantum Mechanics

The Early History of Quantum Mechanics Chapter 2 The Early History of Quantum Mechanics In the early years of the twentieth century, Max Planck, Albert Einstein, Louis de Broglie, Neils Bohr, Werner Heisenberg, Erwin Schrödinger, Max Born,

More information

Measurement of Charge-to-Mass (e/m) Ratio for the Electron

Measurement of Charge-to-Mass (e/m) Ratio for the Electron Measurement of Charge-to-Mass (e/m) Ratio for the Electron Experiment objectives: measure the ratio of the electron charge-to-mass ratio e/m by studying the electron trajectories in a uniform magnetic

More information

Wave Function, ψ. Chapter 28 Atomic Physics. The Heisenberg Uncertainty Principle. Line Spectrum

Wave Function, ψ. Chapter 28 Atomic Physics. The Heisenberg Uncertainty Principle. Line Spectrum Wave Function, ψ Chapter 28 Atomic Physics The Hydrogen Atom The Bohr Model Electron Waves in the Atom The value of Ψ 2 for a particular object at a certain place and time is proportional to the probability

More information

Geometric Optics Physics 118/198/212. Geometric Optics

Geometric Optics Physics 118/198/212. Geometric Optics Background Geometric Optics This experiment deals with image formation with lenses. We will use what are referred to as thin lenses. Thin lenses are ordinary lenses like eyeglasses and magnifiers, but

More information

An Introduction to the Cathode-Ray Tube

An Introduction to the Cathode-Ray Tube March 7, 2005 An Introduction to the Cathode-Ray Tube Prepared for Ann Holms University of California, Santa Barbara Prepared by Student Name University of California, Santa Barbara Abstract The cathode-ray

More information

LIGHT AND ELECTROMAGNETIC RADIATION

LIGHT AND ELECTROMAGNETIC RADIATION LIGHT AND ELECTROMAGNETIC RADIATION Light is a Wave Light is a wave motion of radiation energy in space. We can characterize a wave by three numbers: - wavelength - frequency - speed Shown here is precisely

More information

The Phenomenon of Photoelectric Emission:

The Phenomenon of Photoelectric Emission: The Photoelectric Effect. The Wave particle duality of light Light, like any other E.M.R (electromagnetic radiation) has got a dual nature. That is there are experiments that prove that it is made up of

More information

Theremino System Theremino Spectrometer Technology

Theremino System Theremino Spectrometer Technology Theremino System Theremino Spectrometer Technology theremino System - Theremino Spectrometer Technology - August 15, 2014 - Page 1 Operation principles By placing a digital camera with a diffraction grating

More information

Level 3 Achievement Scale

Level 3 Achievement Scale Unit 1: Atoms Level 3 Achievement Scale Can state the key results of the experiments associated with Dalton, Rutherford, Thomson, Chadwick, and Bohr and what this lead each to conclude. Can explain that

More information

Teaching Time: Two 50-minute periods

Teaching Time: Two 50-minute periods Lesson Summary In this lesson, students will build an open spectrograph to calculate the angle the light is transmitted through a holographic diffraction grating. After finding the desired angles, the

More information

VISIBLE SPECTROSCOPY

VISIBLE SPECTROSCOPY VISIBLE SPECTROSCOPY Visible spectroscopy is the study of the interaction of radiation from the visible part (λ = 380-720 nm) of the electromagnetic spectrum with a chemical species. Quantifying the interaction

More information

Arrangement of Electrons in Atoms

Arrangement of Electrons in Atoms CHAPTER 4 PRE-TEST Arrangement of Electrons in Atoms In the space provided, write the letter of the term that best completes each sentence or best answers each question. 1. Which of the following orbital

More information

UNIT 2 - ATOMIC THEORY

UNIT 2 - ATOMIC THEORY UNIT 2 - ATOMIC THEORY VOCABULARY: Allotrope Anion Atom Atomic Mass Atomic Mass unit (a.m.u.) Atomic number Bohr model Cation Compound Electron Electron Configuration Element Excited state Ground state

More information

Chapter 5. Mendeleev s Periodic Table

Chapter 5. Mendeleev s Periodic Table Chapter 5 Perodicity and Atomic Structure Mendeleev s Periodic Table In the 1869, Dmitri Mendeleev proposed that the properties of the chemical elements repeat at regular intervals when arranged in order

More information

BOHR S THEORY AND PHYSICS OF ATOM CHAPTER 43

BOHR S THEORY AND PHYSICS OF ATOM CHAPTER 43 1. a BOHR S THEORY AND PHYSICS OF ATOM CHAPTER 3 1 h A T (ML T ) M L T 3 L me L MLT M(AT) M L T a has dimensions of length.. We know, 1/ 1.1 1 (1/n 1 1/n ) a) n 1, n 3 or, 1/ 1.1 1 (1/ 1/9) 36 or, 6.5

More information

CHM1 Exam 4 Review. Topics. 1. Structure of the atom a. Proton nucleus + 1 amu b. Neutron nucleus 0 1 amu c. Electron orbits - 0 amu 2.

CHM1 Exam 4 Review. Topics. 1. Structure of the atom a. Proton nucleus + 1 amu b. Neutron nucleus 0 1 amu c. Electron orbits - 0 amu 2. Topics 1. Structure of the atom a. Proton nucleus + 1 amu b. Neutron nucleus 0 1 amu c. Electron orbits - 0 amu 2. Atomic symbols Mass number (protons + neutrons) 4+ charge 126C atomic number (# protons)

More information

M01/430/H(3) Name PHYSICS HIGHER LEVEL PAPER 3. Number. Wednesday 16 May 2001 (morning) 1 hour 15 minutes INSTRUCTIONS TO CANDIDATES

M01/430/H(3) Name PHYSICS HIGHER LEVEL PAPER 3. Number. Wednesday 16 May 2001 (morning) 1 hour 15 minutes INSTRUCTIONS TO CANDIDATES INTERNATIONAL BACCALAUREATE BACCALAURÉAT INTERNATIONAL BACHILLERATO INTERNACIONAL M01/430/H(3) PHYSICS HIGHER LEVEL PAPER 3 Wednesday 16 May 2001 (morning) Name Number 1 hour 15 minutes INSTRUCTIONS TO

More information

Investigating electromagnetic radiation

Investigating electromagnetic radiation Investigating electromagnetic radiation Announcements: First midterm is 7:30pm on 2/17/09 Problem solving sessions M3-5 and T3-4,5-6. Homework due at 12:50pm on Wednesday. We are covering Chapter 4 this

More information

Atomic Calculations. 2.1 Composition of the Atom. number of protons + number of neutrons = mass number

Atomic Calculations. 2.1 Composition of the Atom. number of protons + number of neutrons = mass number 2.1 Composition of the Atom Atomic Calculations number of protons + number of neutrons = mass number number of neutrons = mass number - number of protons number of protons = number of electrons IF positive

More information

The Shoebox spectrograph construction and lab investigations. By Timothy Grove

The Shoebox spectrograph construction and lab investigations. By Timothy Grove The Shoebox spectrograph construction and lab investigations By Timothy Grove 1 Part 1. Build your own spectrograph from flat cardboard Tools and materials: Necessary items Scrap cardboard (You will need

More information

Atomic Structure: Chapter Problems

Atomic Structure: Chapter Problems Atomic Structure: Chapter Problems Bohr Model Class Work 1. Describe the nuclear model of the atom. 2. Explain the problems with the nuclear model of the atom. 3. According to Niels Bohr, what does n stand

More information

Sample Exercise 6.1 Concepts of Wavelength and Frequency

Sample Exercise 6.1 Concepts of Wavelength and Frequency Sample Exercise 6.1 Concepts of Wavelength and Frequency Two electromagnetic waves are represented in the margin. (a) Which wave has the higher frequency? (b) If one wave represents visible light and the

More information

Austin Peay State University Department of Chemistry Chem 1111. The Use of the Spectrophotometer and Beer's Law

Austin Peay State University Department of Chemistry Chem 1111. The Use of the Spectrophotometer and Beer's Law Purpose To become familiar with using a spectrophotometer and gain an understanding of Beer s law and it s relationship to solution concentration. Introduction Scientists use many methods to determine

More information

Friday 18 January 2013 Morning

Friday 18 January 2013 Morning Friday 18 January 2013 Morning AS GCE PHYSICS B (ADVANCING PHYSICS) G492/01 Understanding Processes / Experimentation and Data Handling *G411640113* Candidates answer on the Question Paper. OCR supplied

More information

UNIT: Electromagnetic Radiation and Photometric Equipment

UNIT: Electromagnetic Radiation and Photometric Equipment UNIT: Electromagnetic Radiation and Photometric Equipment 3photo.wpd Task Instrumentation I To review the theory of electromagnetic radiation and the principle and use of common laboratory instruments

More information

Quantum Mechanics and Atomic Structure 1

Quantum Mechanics and Atomic Structure 1 Quantum Mechanics and Atomic Structure 1 INTRODUCTION The word atom is derived from the Greek word, atomos, which means uncut or indivisible. It was Dalton (1808) who established that elementary constituents

More information

The Advanced Placement Examination in Chemistry. Part I Multiple Choice Questions Part II Free Response Questions Selected Questions from1970 to 2010

The Advanced Placement Examination in Chemistry. Part I Multiple Choice Questions Part II Free Response Questions Selected Questions from1970 to 2010 The Advanced Placement Examination in Chemistry Part I Multiple Choice Questions Part II Free Response Questions Selected Questions from1970 to 2010 Atomic Theory and Periodicity Part I 1984 1. Which of

More information

CONCAVE DIFFRACTION GRATING SPECTROGRAPH

CONCAVE DIFFRACTION GRATING SPECTROGRAPH CONCAVE DIFFRACTION GRATING SPECTROGRAPH Revised May 16, 2006 Diffraction gratings are widely used for high resolution spectral studies. The grating available in the lab is a holographically-produced,

More information

Electron Orbits. Binding Energy. centrifugal force: electrostatic force: stability criterion: kinetic energy of the electron on its orbit:

Electron Orbits. Binding Energy. centrifugal force: electrostatic force: stability criterion: kinetic energy of the electron on its orbit: Electron Orbits In an atom model in which negatively charged electrons move around a small positively charged nucleus stable orbits are possible. Consider the simple example of an atom with a nucleus of

More information

6) How wide must a narrow slit be if the first diffraction minimum occurs at ±12 with laser light of 633 nm?

6) How wide must a narrow slit be if the first diffraction minimum occurs at ±12 with laser light of 633 nm? Test IV Name 1) In a single slit diffraction experiment, the width of the slit is 3.1 10-5 m and the distance from the slit to the screen is 2.2 m. If the beam of light of wavelength 600 nm passes through

More information

Thomson and Rayleigh Scattering

Thomson and Rayleigh Scattering Thomson and Rayleigh Scattering Initial questions: What produces the shapes of emission and absorption lines? What information can we get from them regarding the environment or other conditions? In this

More information

Basic Optics System OS-8515C

Basic Optics System OS-8515C 40 50 30 60 20 70 10 80 0 90 80 10 20 70 T 30 60 40 50 50 40 60 30 C 70 20 80 10 90 90 0 80 10 70 20 60 50 40 30 Instruction Manual with Experiment Guide and Teachers Notes 012-09900B Basic Optics System

More information

Outline. Chapter 6 Electronic Structure and the Periodic Table. Review. Arranging Electrons in Atoms. Fireworks. Atomic Spectra

Outline. Chapter 6 Electronic Structure and the Periodic Table. Review. Arranging Electrons in Atoms. Fireworks. Atomic Spectra Outline William L Masterton Cecile N. Hurley Edward J. Neth cengage.com/chemistry/masterton Chapter 6 Electronic Structure and the Periodic Table Light, photon energies and atomic spectra The hydrogen

More information

P R E A M B L E. Facilitated workshop problems for class discussion (1.5 hours)

P R E A M B L E. Facilitated workshop problems for class discussion (1.5 hours) INSURANCE SCAM OPTICS - LABORATORY INVESTIGATION P R E A M B L E The original form of the problem is an Experimental Group Research Project, undertaken by students organised into small groups working as

More information

emission of light from atoms discrete line spectra - energy levels, Franck-Hertz experiment

emission of light from atoms discrete line spectra - energy levels, Franck-Hertz experiment Introduction Until the early 20 th century physicists used to explain the phenomena in the physical world around them using theories such a mechanics, electromagnetism, thermodynamics and statistical physics

More information

GEOMETRICAL OPTICS. Lens Prism Mirror

GEOMETRICAL OPTICS. Lens Prism Mirror GEOMETRICAL OPTICS Geometrical optics is the treatment of the passage of light through lenses, prisms, etc. by representing the light as rays. A light ray from a source goes in a straight line through

More information

Reflection and Refraction

Reflection and Refraction Equipment Reflection and Refraction Acrylic block set, plane-concave-convex universal mirror, cork board, cork board stand, pins, flashlight, protractor, ruler, mirror worksheet, rectangular block worksheet,

More information

From lowest energy to highest energy, which of the following correctly orders the different categories of electromagnetic radiation?

From lowest energy to highest energy, which of the following correctly orders the different categories of electromagnetic radiation? From lowest energy to highest energy, which of the following correctly orders the different categories of electromagnetic radiation? From lowest energy to highest energy, which of the following correctly

More information

CHAPTER 6: ANSWERS TO ASSIGNED PROBLEMS Hauser- General Chemistry I revised 8/03/08

CHAPTER 6: ANSWERS TO ASSIGNED PROBLEMS Hauser- General Chemistry I revised 8/03/08 CHAPTER 6: ANSWERS TO ASSIGNED PROBLEMS Hauser- General Chemistry I revised 8/03/08 6.9 What are the basic SI units for? (a) the wavelength of light meters, although colors are usually reported in 3 digit

More information

Experiment #5: Qualitative Absorption Spectroscopy

Experiment #5: Qualitative Absorption Spectroscopy Experiment #5: Qualitative Absorption Spectroscopy One of the most important areas in the field of analytical chemistry is that of spectroscopy. In general terms, spectroscopy deals with the interactions

More information

Blackbody Radiation References INTRODUCTION

Blackbody Radiation References INTRODUCTION Blackbody Radiation References 1) R.A. Serway, R.J. Beichner: Physics for Scientists and Engineers with Modern Physics, 5 th Edition, Vol. 2, Ch.40, Saunders College Publishing (A Division of Harcourt

More information

1 Laboratory #5: Grating Spectrometer

1 Laboratory #5: Grating Spectrometer SIMG-215-20061: LABORATORY #5 1 Laboratory #5: Grating Spectrometer 1.1 Objective: To observe and measure the spectra of different light sources. 1.2 Materials: 1. OSA optics kit. 2. Nikon digital camera

More information

Using a spectrohelioscope to observe the sun's corona

Using a spectrohelioscope to observe the sun's corona Using a spectrohelioscope to observe the sun's corona One of the most inspiring natural spectacles is that of the fiery prominences that shoot out from the surface of the sun. It is unfortunate that most

More information

AP* Atomic Structure & Periodicity Free Response Questions KEY page 1

AP* Atomic Structure & Periodicity Free Response Questions KEY page 1 AP* Atomic Structure & Periodicity ree Response Questions KEY page 1 1980 a) points 1s s p 6 3s 3p 6 4s 3d 10 4p 3 b) points for the two electrons in the 4s: 4, 0, 0, +1/ and 4, 0, 0, - 1/ for the three

More information

!! Regarding the information about figures (Fig.XY) please have a look at the german version!! Spektroscopy

!! Regarding the information about figures (Fig.XY) please have a look at the german version!! Spektroscopy 1. Introduction (under construction) Spektroscopy 2. Prism and Grid Spectrometers Basics of Construction and Operation The experiment can be conducted with one of two types of spectrometer in which the

More information

UC Irvine FOCUS! 5 E Lesson Plan

UC Irvine FOCUS! 5 E Lesson Plan UC Irvine FOCUS! 5 E Lesson Plan Title: Flame Tests Grade Level and Course: 7 th Grade Life Science, 8 th Grade Physical Science, 9-12 th Grade Chemistry Materials: Spatulas (straws cut at an angle) Sterno

More information

Lecture 1. The nature of electromagnetic radiation.

Lecture 1. The nature of electromagnetic radiation. Lecture 1. The nature of electromagnetic radiation. 1. Basic introduction to the electromagnetic field: Dual nature of electromagnetic radiation Electromagnetic spectrum. Basic radiometric quantities:

More information

Mr. Dolgos Regents Chemistry NOTE PACKET. Unit 2: Atomic Theory

Mr. Dolgos Regents Chemistry NOTE PACKET. Unit 2: Atomic Theory *STUDENT* *STUDENT* Mr. Dolgos Regents Chemistry NOTE PACKET Unit 2: Atomic Theory 1 *STUDENT* UNIT 2 - ATOMIC THEORY *STUDENT* VOCABULARY: Allotrope Anion Atom Atomic Mass Atomic Mass unit (a.m.u.) Atomic

More information

13- What is the maximum number of electrons that can occupy the subshell 3d? a) 1 b) 3 c) 5 d) 2

13- What is the maximum number of electrons that can occupy the subshell 3d? a) 1 b) 3 c) 5 d) 2 Assignment 06 A 1- What is the energy in joules of an electron undergoing a transition from n = 3 to n = 5 in a Bohr hydrogen atom? a) -3.48 x 10-17 J b) 2.18 x 10-19 J c) 1.55 x 10-19 J d) -2.56 x 10-19

More information

Chemistry 102 Summary June 24 th. Properties of Light

Chemistry 102 Summary June 24 th. Properties of Light Chemistry 102 Summary June 24 th Properties of Light - Energy travels through space in the form of electromagnetic radiation (EMR). - Examples of types of EMR: radio waves, x-rays, microwaves, visible

More information

Chapter 6 Electronic Structure of Atoms

Chapter 6 Electronic Structure of Atoms Chapter 6 Electronic Structure of Atoms 1. Electromagnetic radiation travels through vacuum at a speed of m/s. (a). 6.626 x 26 (b). 4186 (c). 3.00 x 8 (d). It depends on wavelength Explanation: The speed

More information

Lab M1: The Simple Pendulum

Lab M1: The Simple Pendulum Lab M1: The Simple Pendulum Introduction. The simple pendulum is a favorite introductory exercise because Galileo's experiments on pendulums in the early 1600s are usually regarded as the beginning of

More information