radiology physics 1

Introduction to Medical Imaging – Chapter 1Radiation and the Atom – Chapter 2

3 and 10 July 2008

© UW and Brent K Stewart, PhD, DABMP 1

©© UW and UW and Brent K. Stewart PhD, DABMPBrent K. Stewart PhD, DABMP 11

Introduction to Medical Imaging Introduction to Medical Imaging –– Chapter 1Chapter 1Radiation and the Atom Radiation and the Atom –– Chapter 2Chapter 2

Brent K. Stewart, PhD, DABMPBrent K. Stewart, PhD, DABMPProfessor, Radiology and Medical EducationProfessor, Radiology and Medical Education

Director, Diagnostic PhysicsDirector, Diagnostic Physics

a copy of this lecture may be found at:a copy of this lecture may be found at:http://courses.washington.edu/radxphys/PhysicsCourse.htmlhttp://courses.washington.edu/radxphys/PhysicsCourse.html

©© UW and Brent K. Stewart PhD, DABMPUW and Brent K. Stewart PhD, DABMP 22

Diagnostic Radiology Imaging PhysicsDiagnostic Radiology Imaging Physics20082008--2009 Course Topics (hours)2009 Course Topics (hours)

�� Atom, Radiation & Matter (3)Atom, Radiation & Matter (3)�� Computers, Networks, PACS Computers, Networks, PACS

and Teleradiology (1)and Teleradiology (1)�� XX--ray Production (2)ray Production (2)�� ScreenScreen--Film Radiography (2)Film Radiography (2)�� Film Processing (offFilm Processing (off--line)line)�� Image Quality (2)Image Quality (2)�� Radiation Protection and Radiation Protection and

Radiation Dosimetry (2)Radiation Dosimetry (2)�� Radiation Biology (2)Radiation Biology (2)�� Fluoroscopy (2)Fluoroscopy (2)�� Computed and DigitalComputed and Digital

Radiography (2)Radiography (2)�� Radiological Adjuncts (offRadiological Adjuncts (off--line)line)�� Computed Tomography (5)Computed Tomography (5)�� Ultrasound (3)Ultrasound (3)�� Nuclear Magnetic Resonance Nuclear Magnetic Resonance

(2)(2)�� Magnetic Resonance Imaging Magnetic Resonance Imaging

(6)(6)�� Mammography (3)Mammography (3)�� Lab and Q&A Review (3)Lab and Q&A Review (3)�� Nuclear Medicine (6)Nuclear Medicine (6)�� Total = 46 contact hoursTotal = 46 contact hours


Chapters 1 & 2 Lecture ObjectivesChapters 1 & 2 Lecture Objectives

�� Intro to Medical Imaging Intro to Medical Imaging –– what are we after technically?what are we after technically?�� Spatial ResolutionSpatial Resolution�� ContrastContrast

�� Generally describe what processes are involved in the Generally describe what processes are involved in the diagnostic radiology imaging chaindiagnostic radiology imaging chain

�� Describe the basic characteristics of electromagnetic Describe the basic characteristics of electromagnetic ((((00) radiation and how they are mathematically related) radiation and how they are mathematically related

�� Describe how atomic electronic structure determines the Describe how atomic electronic structure determines the characteristics of emitted characteristics of emitted ((00 radiationradiation

�� Particulate radiation and the atomic nucleus Particulate radiation and the atomic nucleus –– whatwhat’’s the s the matter?matter?


What a Nobel Path you TreadWhat a Nobel Path you Tread

�� Roentgen (1901, physics): discovery of xRoentgen (1901, physics): discovery of x--radiationradiation�� Rabi (1944, physics): nuclear magnetic resonance Rabi (1944, physics): nuclear magnetic resonance

(NMR) methodology(NMR) methodology�� Bloch and Purcell (1952, physics): NMR precision Bloch and Purcell (1952, physics): NMR precision

measurementsmeasurements�� Cormack and Hounsfield (1979, medicine): computed Cormack and Hounsfield (1979, medicine): computed

assisted tomography (CT)assisted tomography (CT)�� Ernst (1991, chemistry): highErnst (1991, chemistry): high--resolution NMR resolution NMR

spectroscopyspectroscopy�� Laterbur and Mansfield (2003, medicine): discoveries Laterbur and Mansfield (2003, medicine): discoveries

concerning magnetic resonance imaging (MRI)concerning magnetic resonance imaging (MRI)


3 and 10 July 2008



Introduction to Medical ImagingIntroduction to Medical Imaging

�� Medical imaging requires some form of radiation capable Medical imaging requires some form of radiation capable of penetrating tissuesof penetrating tissues

�� This radiation must interact with the bodyThis radiation must interact with the body’’s various s various tissues in some tissues in some differentialdifferential manner to provide manner to provide contrastcontrast

�� The diagnostic utility of a medical image relates to both The diagnostic utility of a medical image relates to both technical technical image qualityimage quality and acquisition conditionsand acquisition conditions

�� Image qualityImage quality results from many traderesults from many trade--offsoffs�� Patient safetyPatient safety –– levels of radiation utilized (levels of radiation utilized (ALARAALARA))�� Spatial resolutionSpatial resolution�� Temporal resolutionTemporal resolution�� Noise propertiesNoise properties


MRI

Transparency of Human Body to Transparency of Human Body to ((00 RadiationRadiation

c.f. c.f. Macovski, A. Medical Imaging Systems, p. 3.Macovski, A. Medical Imaging Systems, p. 3.


XX--rays rays –– the Basic Radiological Toolthe Basic Radiological Tool

Roentgen’s experimental apparatus (Crookes tube) that led to the discovery of the new radiation on 8 Nov. 1895 – he demonstrated that the radiation was not due to charged particles, but due to an as yet unknown source, hence “x” radiation or “x-rays”

Known as “the radiograph of Bera Roentgen’s hand” taken 22 Dec. 1895


NMR T1 for Tumor and Normal TissueNMR T1 for Tumor and Normal Tissue

c.f. c.f. Damadian, R, et al. Damadian, R, et al. PNASPNAS 1974; 71: 14711974; 71: 1471--3.3.


3 and 10 July 2008



Agent Scully, canAgent Scully, can’’t you tell the difference between a CT t you tell the difference between a CT and MR image? Whatand MR image? What’’s a Ps a P--EE--T scanner anyway?T scanner anyway?

c.f.c.f. http://www.askdrscully.com/http://www.askdrscully.com/

Looking for Mulder’s brain?

Not just for Fido anymore:

arf-arf!


A Systematic Approach to Medical ImagingA Systematic Approach to Medical Imaging


XX--ray Computed Tomographyray Computed Tomography

XX--ray Tuberay Tube

DetectorsDetectors

CT TableCT Table

XX--ray Beamray Beam

XX--ray Tuberay Tube

DetectorsDetectors

CT TableCT Table

XX--ray Beamray Beam

Figure from Dr. Mahesh, John Figure from Dr. Mahesh, John Hopkins, MD, AAPM Handout.Hopkins, MD, AAPM Handout.


Magnetic Resonance ImagingMagnetic Resonance Imaging

2D FT2D FT

···

···

+k

-k-k -k

···

···

+k

-k-k -k

2D FT2D FT

···

···

+k

-k-k -k

···

···

+k

-k-k -k

: 2D FT2D FT

···

···

+k

-k-k -k

···

···

+k

-k-k -k

···

···

+k

-k-k -k

···

···

+k

-k-k -k

2D FT2D FT

···

···

+k

-k-k -k

···

···

+k

-k-k -k

···

···

+k

-k-k -k

···

···

+k

-k-k -k

···

···

+k

-k-k -k

···

···

+k

-k-k -k

:

c.f. Bushberg, et al. The Essential Physics of c.f. Bushberg, et al. The Essential Physics of Medical Imaging, 2Medical Imaging, 2ndnd ed., pp. 426, 429 & 461.ed., pp. 426, 429 & 461.


3 and 10 July 2008



UltrasoundUltrasound

c.f. Bushberg, et al. The Essential Physics c.f. Bushberg, et al. The Essential Physics of Medical Imaging, 2of Medical Imaging, 2ndnd ed., p. 501.ed., p. 501.

c.f. c.f. http://www.cs.adelaide.edu.au/~evan/http://www.cs.adelaide.edu.au/~evan/project/prog1.htmproject/prog1.htm ©© UW and Brent K. Stewart PhD, DABMPUW and Brent K. Stewart PhD, DABMP 1414

Nuclear Medicine/Positron Emission TomographyNuclear Medicine/Positron Emission Tomography

c.f. c.f. http://www.griffwason.com/gw_images/http://www.griffwason.com/gw_images/MRI_scanner/glwMRI_scanner/glw--pet_scanner1.jpgpet_scanner1.jpg

c.f. c.f. http://www.medscape.com/content/2003/http://www.medscape.com/content/2003/00/45/79/457982/art00/45/79/457982/art--ar457982.fig10.jpgar457982.fig10.jpg


Spatial Resolution Spatial Resolution –– What are the limits?What are the limits?

c.f. Bushberg, et al. The Essential Physics c.f. Bushberg, et al. The Essential Physics of Medical Imaging, 2of Medical Imaging, 2ndnd ed., p. 15.ed., p. 15. ©© UW and Brent K. Stewart PhD, DABMPUW and Brent K. Stewart PhD, DABMP 1616

Contrast Contrast –– What does it depend on?What does it depend on?

�� Radiation must interact with the bodyRadiation must interact with the body’’s various tissues in s various tissues in some some differentialdifferential manner to provide manner to provide contrastcontrast

�� XX--ray/CT: differences in eray/CT: differences in e-- density (edensity (e--/cm/cm33 = = U�U�·· ee--/gr)/gr)�� Ultrasound: differences in acoustic impedance (Z = Ultrasound: differences in acoustic impedance (Z = UU··c)c)�� MRI: endogenous and exogenous differencesMRI: endogenous and exogenous differences

�� endogenous: T1, T2, endogenous: T1, T2, UUHH, flow, perfusion, diffusion, flow, perfusion, diffusion�� exogenous: TR, TE, and TIexogenous: TR, TE, and TI

�� NM: concentration (NM: concentration (UU) of radionuclide or ) of radionuclide or EE++ emitteremitter�� Contrast agents exaggerate natural contrast levelsContrast agents exaggerate natural contrast levels

�� Iodinated (xIodinated (x--ray/CT)ray/CT)�� Paramagnetic (MRI)Paramagnetic (MRI)�� Microspheres (US)Microspheres (US)


3 and 10 July 2008



Radiation and the Physics of Medical ImagingRadiation and the Physics of Medical Imaging

�� ““Without radiation, life itself would Without radiation, life itself would be impossiblebe impossible”” –– Prof. StewartProf. Stewart

�� ““Radiation is all around us. From Radiation is all around us. From natural sources like the Sun to natural sources like the Sun to man made sources that provide man made sources that provide life saving medical benefits, life saving medical benefits, smoke detectors, etc...smoke detectors, etc...””-- nuclearactive.comnuclearactive.com

�� ““YouYou’’re soaking in itre soaking in it”” –– Madge, Madge, Palmolive spokeswomanPalmolive spokeswoman

�� ““10 10 PPGy/day keeps the Dr. awayGy/day keeps the Dr. away””�� "It"It’’s not the volts thats not the volts that’’ll get ya, itll get ya, it’’s s

the amps.the amps.““ –– Billy Crystal, Billy Crystal, Running ScaredRunning Scared


RadiationRadiation

�� The propagation of energy through:The propagation of energy through:�� SpaceSpace�� MatterMatter

�� Can be thought of as either:Can be thought of as either:�� Corpuscular (particles, e.g., electron)Corpuscular (particles, e.g., electron)�� Electromagnetic (Electromagnetic (((00))�� AcousticAcoustic

�� Acoustic radiation awaits the ultrasound sessions later Acoustic radiation awaits the ultrasound sessions later on in the courseon in the course


Characterization of WavesCharacterization of Waves

�� Amplitude: intensity of the waveAmplitude: intensity of the wave�� Wavelength (Wavelength (OO): distance between identical points on adjacent ): distance between identical points on adjacent

cycles [m, nm] (1 nm = 10cycles [m, nm] (1 nm = 10--99 m)m)�� Period (Period (WW): time required to complete one cycle (): time required to complete one cycle (OO) of a wave [sec]) of a wave [sec]�� Frequency (Frequency (QQ): number of periods per second = (1/): number of periods per second = (1/WW) [Hz or sec) [Hz or sec--11] ] �� Speed of radiation: Speed of radiation: c = c = OO ·· QQ [m/sec][m/sec]

c.f. c.f. Bushberg, et al. The Essential Physics Bushberg, et al. The Essential Physics of Medical Imaging, 2of Medical Imaging, 2ndnd ed., p.18.ed., p.18. ©© UW and Brent K. Stewart PhD, DABMPUW and Brent K. Stewart PhD, DABMP 2020

Electromagnetic (Electromagnetic (((00) Radiation) Radiation

�� ((00 radiation consists of the transport of energy through radiation consists of the transport of energy through space as a combination of an electric (space as a combination of an electric ((() and magnetic ) and magnetic ((00) field, both of which vary sinusoidally as a function of ) field, both of which vary sinusoidally as a function of space and time, e.g., space and time, e.g., (((t) = (t) = ((0 0 sin(2sin(2SSct/ct/OO), where ), where OO is the is the wavelength of oscillation and c is the speed of lightwavelength of oscillation and c is the speed of light

c.f. c.f. Bushberg, et al. The Essential Physics Bushberg, et al. The Essential Physics of Medical Imaging, 2of Medical Imaging, 2ndnd ed., p.19.ed., p.19.


3 and 10 July 2008



The Electromagnetic (The Electromagnetic (((00) Spectrum) Spectrum

�� Physical manifestations are classified in the Physical manifestations are classified in the ((00 spectrum based on spectrum based on energy (E) and wavelength (energy (E) and wavelength (OO) and comprise the following general ) and comprise the following general categories:categories:�� Radiant heat, radio waves, microwavesRadiant heat, radio waves, microwaves�� ““LightLight”” –– infrared, visible and ultravioletinfrared, visible and ultraviolet�� XX--rays and gammarays and gamma--rays (high energy rays (high energy ((00 emitted from the nucleus)emitted from the nucleus)

c.f. http://www.uic.com.au/ral.htmc.f. http://www.uic.com.au/ral.htm ©© UW and Brent K. Stewart PhD, DABMPUW and Brent K. Stewart PhD, DABMP 2222

((00 Radiation Share the FollowingRadiation Share the Following

�� Velocity in vacuum (c) = 3 x 10Velocity in vacuum (c) = 3 x 1088 m/secm/sec�� Highly directional travel, esp. for shorter Highly directional travel, esp. for shorter OO�� Interaction with matter via either absorption or scatteringInteraction with matter via either absorption or scattering�� Unaffected by external Unaffected by external (( or or 00 fieldsfields�� Characterized by Characterized by OO, frequency (, frequency (QQ), and energy (), and energy (EE))�� SoSo--called called wavewave--particle dualityparticle duality, the manifestation , the manifestation

depending on E and relative dimensions of the detector depending on E and relative dimensions of the detector to to OO. All . All ((00 radiation has zero mass.radiation has zero mass.

�� *X*X--rays are ionizing radiation, removing bound electrons rays are ionizing radiation, removing bound electrons -- can cause either immediate or latent can cause either immediate or latent biological damagebiological damage


((00 Wave and Particle CharacteristicsWave and Particle Characteristics

�� Wave characteristics Wave characteristics –– used to explain interference and used to explain interference and diffraction phenomena: diffraction phenomena: cc [m/sec] [m/sec] == OO [m] [m] ·· QQ [1/sec][1/sec]�� As c is essentially constant, then As c is essentially constant, then QQ ##1/1/OO (inversely proportional)(inversely proportional)�� Wavelength often measured in nanometers (nm = 10Wavelength often measured in nanometers (nm = 10--99 m)m)�� Frequency measured in Hertz (Hz): Hz = 1/sec or secFrequency measured in Hertz (Hz): Hz = 1/sec or sec--11

c.f. Bushberg, et al. The Essential Physics c.f. Bushberg, et al. The Essential Physics of Medical Imaging, 2of Medical Imaging, 2ndnd ed., p.18.ed., p.18. ©© UW and Brent K. Stewart PhD, DABMPUW and Brent K. Stewart PhD, DABMP 2424

((00 Wave and Particle CharacteristicsWave and Particle Characteristics

�� Particle characteristics Particle characteristics –– when interacting with matter, when interacting with matter, high energy high energy ((00 radiation act as energy quanta:radiation act as energy quanta: photonsphotons

�� EE [Joule] [Joule] = h= hQQ = hc/= hc/OO, where h = Planck, where h = Planck’’s constant s constant (6.62x10(6.62x10--3434 JouleJoule--sec = 4.13x10sec = 4.13x10--1818 keVkeV--sec)sec)

�� If E expressed in keV and If E expressed in keV and OO in nm: in nm: E [keV] = 1.24/E [keV] = 1.24/OO [nm][nm]

c.f. Bushberg, et al. The Essential Physics c.f. Bushberg, et al. The Essential Physics of Medical Imaging, 2of Medical Imaging, 2ndnd ed., p.18.ed., p.18.


3 and 10 July 2008



MRIMRI

Transparency of Human Body to Transparency of Human Body to ((00 RadiationRadiation

c.f. Bushberg, et al. The Essential Physics c.f. Bushberg, et al. The Essential Physics of Medical Imaging, 2of Medical Imaging, 2ndnd ed., p.18.ed., p.18. c.f. c.f. Macovski, A. Medical Imaging Systems, p. 3.Macovski, A. Medical Imaging Systems, p. 3. ©© UW and Brent K. Stewart PhD, DABMPUW and Brent K. Stewart PhD, DABMP 2626

Raphex 2000 Question: Raphex 2000 Question: ((00 RadiationRadiation

�� G46G46. Regarding electromagnetic radiation:. Regarding electromagnetic radiation:�� A. Wavelength is directly proportional to frequency.A. Wavelength is directly proportional to frequency.�� B. Velocity is directly proportional to frequency.B. Velocity is directly proportional to frequency.�� C. Energy is directly proportional to frequency.C. Energy is directly proportional to frequency.�� D. Energy is directly proportional to wavelength.D. Energy is directly proportional to wavelength.�� E. Energy is inversely proportional to frequency.E. Energy is inversely proportional to frequency.



�� G51. G51. Which of the following has the highest photon Which of the following has the highest photon energy?energy?�� A. Radio wavesA. Radio waves�� B. Visible lightB. Visible light�� C. UltrasoundC. Ultrasound�� D. XD. X--raysrays�� E. UltravioletE. Ultraviolet



�� G52. G52. Which of the following has the longest wavelength?Which of the following has the longest wavelength?�� A. Radio wavesA. Radio waves�� B. Visible lightB. Visible light�� C. UltravioletC. Ultraviolet�� D. XD. X--raysrays�� E. Gamma raysE. Gamma rays


3 and 10 July 2008




�� G51G51. Visible light has a wavelength of about 6 x 10. Visible light has a wavelength of about 6 x 10--77 m. m. 6060Co gammas have a wavelength of 10Co gammas have a wavelength of 10--1212 m and an m and an energy of 1.2 MeV. The approximate energy of visible energy of 1.2 MeV. The approximate energy of visible light is:light is:�� A. 720 MeVA. 720 MeV�� B. 72 keVB. 72 keV�� C. 2 eVC. 2 eV�� D. 7.2 x 10D. 7.2 x 10--44 eVeV�� E. 2 x 10E. 2 x 10--66 eVeV

�� EE11 = hc/= hc/OO11 and Eand E22 = hc/= hc/OO22, so E, so E11OO1 1 = hc = E= hc = E22OO22

�� EE22 = E= E11OO11//OO2 2 = (12 x 10= (12 x 1055 eV)(10eV)(10--1212 m)/(6 x 10m)/(6 x 10--77 m) = 2 eVm) = 2 eV


Cartoon of the DayCartoon of the Day

c.f. www.physics.utah.edu/~mohit/Physics_Cartoons.html.c.f. www.physics.utah.edu/~mohit/Physics_Cartoons.html.


Particulate RadiationParticulate Radiation

�� Corpuscular radiations Corpuscular radiations are comprised of moving are comprised of moving particles of matter the particles of matter the energy of which is based energy of which is based on the mass and velocity on the mass and velocity of the particlesof the particles

�� Kinetic energy (KE) Kinetic energy (KE) = = ½½ mm00vv22 (for non(for non--relativistic velocities) relativistic velocities)

�� Simplified Einstein Simplified Einstein massmass--energy relationship: energy relationship: E = mE = m00cc22

�� The most significant particulate The most significant particulate radiations of interest are:radiations of interest are:

�� Alpha particlesAlpha particles ĮĮ2+2+

�� ElectronsElectrons ee--

�� PositronPositron ȕȕ++

�� NegatronsNegatrons ȕȕ--

�� ProtonsProtons pp++

�� NeutronsNeutrons nn00

�� Interactions with matter are Interactions with matter are collisional in nature and are collisional in nature and are governed by the conservation governed by the conservation of energy (E) and momentumof energy (E) and momentum(p = mv).(p = mv).

©© UW and Brent K. Stewart PhD, DABMPUW and Brent K. Stewart PhD, DABMP 3232c.f. c.f. http://www.ktfhttp://www.ktf--split.hr/periodni/en/index.htmlsplit.hr/periodni/en/index.html


3 and 10 July 2008



Electronic Structure Electronic Structure –– Electron OrbitsElectron Orbits

�� Pauli exclusion principlePauli exclusion principle� No two electrons in an atom may

have identical quantum numbers

�� ĺĺ max. max. 2n2n22 electrons per shellelectrons per shell�� Quantum NumbersQuantum Numbers

�� nn: principal q.n. : principal q.n. –– which ewhich e-- shellshell�� ƐƐ: : azimuthal azimuthal –– angular momentum angular momentum

q.n. (q.n. (ƐƐ = 0, 1, ... , n= 0, 1, ... , n--1)1)�� mmƐƐ: : magnetic q.n. magnetic q.n. –– orientation of orientation of

the ethe e-- magnetic moment in a magnetic moment in a magnetic field (mmagnetic field (mƐƐ = = --ƐƐ, , --ƐƐ+1, ..., 0, +1, ..., 0, ... ... ƐƐ--1, 1, ƐƐ))

�� mmss: : spin q.n. spin q.n. –– direction of the edirection of the e--

spin (mspin (mss = += +½½ or or --½½))


For a more detailed discussion, see - http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/eleorb.html


Electronic Structure Electronic Structure –– Electron Orbits (2)Electron Orbits (2)

c.f. c.f. Hendee, et al. Medical Hendee, et al. Medical Imaging Physics, 4Imaging Physics, 4thth ed., p.13.ed., p.13.

c.f. c.f. Hendee, et al. Medical Hendee, et al. Medical Imaging Physics, 2Imaging Physics, 2ndnd ed., p.4.ed., p.4.

s, p, d, f, g, h, …

©© UW and Brent K. Stewart PhD, DABMPUW and Brent K. Stewart PhD, DABMP 3535c.f. c.f. http://www.ktfhttp://www.ktf--split.hr/periodni/en/index.htmlsplit.hr/periodni/en/index.html ©© UW and Brent K. Stewart PhD, DABMPUW and Brent K. Stewart PhD, DABMP 3636

Electronic Structure Electronic Structure –– Electron Binding EnergyElectron Binding Energy


EEbb vv ZZ22

c.f. c.f. http://astro.uhttp://astro.u--strasbg.fr/~koppen/discharge/strasbg.fr/~koppen/discharge/

Highly suggested, very nice detailed description - http://hyperphysics.phy-astr.gsu.edu/hbase/hyde.html


3 and 10 July 2008



Radiation from Electron TransitionsRadiation from Electron Transitions

�� Characteristic XCharacteristic X--raysrays�� Auger Electrons and Fluorescent Yield (Auger Electrons and Fluorescent Yield (ZZKK): ):

(characteristic x(characteristic x--rays/total)rays/total)�� Preference for Auger ePreference for Auger e-- at low Zat low Z


c.f. c.f. Sorenson, et al. Physics in Sorenson, et al. Physics in Nuclear Medicine, 1Nuclear Medicine, 1stst ed., p.8.ed., p.8. ©© UW and Brent K. Stewart PhD, DABMPUW and Brent K. Stewart PhD, DABMP 3838

The Atomic NucleusThe Atomic Nucleus

�� Covered in Nuclear Medicine course (May 2008)Covered in Nuclear Medicine course (May 2008)�� Composition of the NucleusComposition of the Nucleus

�� Protons and NeutronProtons and Neutron�� Number of protons = ZNumber of protons = Z�� Number of neutrons = NNumber of neutrons = N�� Mass number = A = Z + NMass number = A = Z + N�� Chemical symbol = XChemical symbol = X�� Isotopes: same Z, but different AIsotopes: same Z, but different A�� Notation: Notation: AA

ZZXXNN, but , but AAX uniquely defines an isotope (also written X uniquely defines an isotope (also written as Xas X--A) as X A) as X ĺĺ Z and N = A Z and N = A -- ZZ�� For example For example 131131I or II or I--131, rather than 131, rather than 131131

5353XX7878


Raphex 2000 Question: Raphex 2000 Question: Atomic StructureAtomic Structure

�� G10G10--G14. G14. Give the charge carried by each of the following:Give the charge carried by each of the following:�� A. +4A. +4�� B. +2B. +2�� C. +1C. +1�� D. 0D. 0�� E. E. --11

�� G10G10. Alpha particle. Alpha particle�� G11G11. Neutron. Neutron�� G12G12. Electron. Electron�� G13G13. Positron. Positron�� G14G14. Photon. Photon



�� G17. G17. Tungsten has a KTungsten has a K--shell binding energy of 69.5 keV. shell binding energy of 69.5 keV. Which of the following is true?Which of the following is true?�� A. The LA. The L--shell has a higher binding energy.shell has a higher binding energy.�� B. Carbon has a higher KB. Carbon has a higher K--shell binding energy.shell binding energy.�� C. Two successive 35 keV photons could remove an electron C. Two successive 35 keV photons could remove an electron

from the Kfrom the K--shell.shell.�� D. A 69 keV photon could not remove the KD. A 69 keV photon could not remove the K--shell electron, but shell electron, but

could remove an Lcould remove an L--shell electron.shell electron.


3 and 10 July 2008




�� G18.G18. How many of the following elements have 8 How many of the following elements have 8 electrons in their outer shell?electrons in their outer shell?�� Element:Element: SulphurSulphur Chlorine Argon PotassiumChlorine Argon Potassium�� Z:Z: 16 17 18 1916 17 18 19�� A. NoneA. None�� B. 1B. 1�� C. 2C. 2�� D. 3D. 3�� E. 4E. 4



�� G18.G18. B B The nThe nthth shell can contain a shell can contain a maximummaximumof 2nof 2n22 electrons, but no shell can contain more than 8 if it electrons, but no shell can contain more than 8 if it is the outer shell. The shell filling is as follows:is the outer shell. The shell filling is as follows:

�� Z Z K shell L shell M shell N shellK shell L shell M shell N shell�� SulphurSulphur 16 2 8 6 016 2 8 6 0�� Chlorine Chlorine 17 2 8 7 017 2 8 7 0�� Argon Argon 18 2 8 8 018 2 8 8 0�� Potassium 19 2 8 8 Potassium 19 2 8 8 11

For interactive answer, see - http://www.webelements.com/webelements/elements/text/Ar/econ.html

©© UW and Brent K. Stewart PhD, DABMPUW and Brent K. Stewart PhD, DABMP 4343c.f. c.f. http://www.ktfhttp://www.ktf--split.hr/periodni/en/index.htmlsplit.hr/periodni/en/index.html ©© UW and Brent K. Stewart PhD, DABMPUW and Brent K. Stewart PhD, DABMP 4444


�� G15. G15. 2262268888RaRa contains 88 __________ .contains 88 __________ .

�� A.A. ElectronsElectrons�� B. NeutronsB. Neutrons�� C. NucleonsC. Nucleons�� D. Protons and neutronsD. Protons and neutrons

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