Radiation Concepts – Quizzes

• “A” symbolizes= Atomic Mass Number – protons + neutrons – if He has 2 protons and 4 neutrons, atomic mass number is 6, because protons and neutrons are both weight “1”. Electrons are “0”.
• 10 eV and higher= electromagnetic energies above this level are capable of ioninzing an atom or molecule. – xrays, gamma, and ultraviolet – can all interact with matter, can remove an electron from an orbital shell.
• 2n²= describes the maximum number of electrons that can occupy a given shell
• A neutral or stable atom occurs when= the number or protons equals the number of electrons
• Alpha particles have= 2 neutrons and 2 protons; have a charge of +2; Slow moving, but high energy ; Cannot penetrate material easily (stopped by a piece of paper or a dead layer of skin); Absorbed easily
• Amplitude= intensity of the wave defined by its maximal height.
• an atom is dynamic and ever moving because of its=  electrical nature – it’s in a constant vibrating motion due to the strong positive nuclear force field surround by negatively spinning and orbiting electrons
• An electron’s mass is= relatively insignificant. 1/1836 of that of a proton
• Angstrom= represented by symbol A with a circle over it. Equal to 10 ^ -10 meters (a ten-billionth of a meter).
• As the number of electrons and protons increases= so does the binding energy of a given electron – due to the increase in the positive charge in the nucleus
• Atom= a very small invisible particle – the smallest particle of an element that still possesses the chemical properties of that element. 92 naturally occurring elements.
• Atomic mass number (A) = the number of protons and neutrons in the nucleus – used when precision is not necessary; protons have a mass of 1; neutrons have a mass of 1; electrons have a mass of 0
• Atomic mass units (amu) describes the  mass of particles of an atom
• Atomic number or Z number= the number of nuclear protons in an atom
• Atoms that have exactly 8 electrons in the outermost shell are= inert and chemically stable – noble gases
• Beta particles are= high-speed electrons; Have a charge of -1 or +1 (either a negatron or positron)
• Diagnostic X-rays wavelength= 0.1-0.5 A.
• During radioactive decay= atoms of an element change into atoms of a different element (radium decays and forms radon)
• Each elements in the last group of 8 elements has            8 electrons in its outermost shell – very stable atoms
• Each individual particle has its own= unique mass
• Electromagnetic energy=result of electric and magnetic disturbances in space. Travels through space and is produced by the acceleration of a charge. Radio waves, microwaves, infrared light, visible light and cosmic rays. X-rays are man-made electromagnetic energy. Pure energy.
• Electromagnetic radiation (EM)= a natural part of the enivornment – forms of it are: visible light, cosmic rays, terrestrial radiation (emitted from deposits of uranium, thorium, and other radioactive substances found in the earth), radionuclides (potassium-40 is part of the human metabolism.)
• Electron binding energy (BE)= the amount of energy needed to remove the electron from the atom.
• Electron binding energy (glue) is measured in= KeV
• Electron volt (eV)=  unit of measure of the binding energy of an electron – also measures x-ray energies – the energy one electron will have when it is accelerated by an electrical potential of one volt
• Electrons cannot be divided into= smaller parts
• Electrons in atoms of high atomic number elements are= bound more tightly than electrons in atoms of lower atomic number elements
• Elements used as contrast media= iodine and barium
• EM waves are unique in that=no medium is required – travel in a vacuum
• Energy level (shell)= distance from the nucleus
• Energy= the ability to do work
• Excitation= transferring energy to an atom by moving electrons to a higher energy state without actually removing them from the atom
• Fast moving, medium energy; can penetrate material well to a degree – stopped by 100-150 pieces of paper or .5-1 cm of water; can’t penetrate down to the level of human organs.
• Frequency and wavelength are= inversely proportional
• Frequency= number of waves that passes a particular point in a given frame, or number of cycles per second. Represented by Greek letter nu (v). Low frequency – radio wave, high frequency – gamma rays.
• Gamma rays originate from= the nucleus of radioactive materials.
• Hertz (Hz)= the unit of frequency
• Hydrogen, helium and lead’s atomic numbers= 1, 2, and 82
• If an atom gains or losses electrons, it results in an= ion – the atom is said to be ionized
• If an atom gains or losses neutrons, it results in an= isotope
• If an electron is added to an atom, it becomes a= negative ion – extra negative charge
• If an electron is removed from an atom, it becomes a= positive ion – extra positive charge
• If an elements as a valence of +1= it will freely give up this electron to bind with another element to form a compound – has one e- in the outer shell
• If an elements as a valence of -1= it has 7 electrons in its outermost shell and will freely accept an electron to bind with another element to form a compound – Salt – NaCl. Na has a valence of +1, and Cl has a valence of -1.
• If wavelength decreases= frequency will increase
• In a zero gravity environment, an object may be= weightless – but the mass of that object would remain unchanged
• Ionization= process of adding or removing an electron from an atom
• Isotopes= atoms that have the same number of protons in the nucleus but different number of neutrons – deuterium is an isotope of hydrogen
• Joule (J) = the unit of energy
• K shell= orbital shell closest to the nucleus = n=1
• keV= kilo-electron volt – 1000 electron volts – unit used to express x-ray and binding energies
• K-shell of lead is= more tightly bound and more difficult to remove the the atom than a K-shell electron of smaller atomic number elements like H or O.
• Law of Conservation= at the basis of Einstein’s work. The sum total of all matter and energy in the universe is a constant. Matter and energy cannot be created or destroyed by can be converted from one form to another.
• Lead has a higher number of protons, so it takes= more energy to remove an orbital e- from the atom – more likely to be absorbed
• M theory= electrons and quarks may not be particles but instead may be small loops of rapidly vibrating string-like matter. Matter may behave differently depending on the vibrations of the string – like a guitar
• Mass of a neutron is= 1.675 x 10 ^-27 kg
• Mass= the quantity of matter contained in an object – best described by its energy equivalence. Mass is constant – it does not change under the influence of gravity. Mass remains unchanged when matter changes from one form to another. Even if 0 gravity, Ice, water, and steam all have the same mass.
• Matter= anything that has mass and occupies space – shape, form and occupies space
• Maximum number of electrons is each shell= K = 2(1) ² = 2; L = 8; M = 18; N = 32; O = 50; P = 72;Q = 98
• Neutrons have a mass xx times the mass of electrons= 1,838 times
• Niels Bohr= expanded the atom model – like a solar system where the electrons orbit around a central nucleus like planets revolve around the sun.
• Noble gases are= inert and chemically stable because they have 8 electrons in their outermost shells – Octect rule
• Nucleons= protons and neutrons together
• Nucleus=small, dense center surrounded by electrons that orbit at various levels. – contains protons and neutrons
• Number of horizontal periods= 7 – all elements in a period have the same principle quantum number (number of electron shells)
• Number of vertical groups= 8 – all elements in a group have the same outer electron configuration.
• Octet rule= the number of electrons in the outermost shell never exceed 8 electrons
• Particle theory= when high-frequency EM radiation interacts with matter, it behaves more like a particle than a wave. EM acts like a small bundle of energy – capable of physically ejecting an e-
• Period= time required to complete one cycle of the wave
• Periodic table lists the elements in= ascending order according to the atomic number
• Photon energy and frequency are= directly proportional. If frequency of an x-ray is doubled, the energy is doubled.
• photon energy and frequency formula= E=hv or v = E/h; E – photon energy (eV); h = Planck’s constant (4.15 x 10 ^ -15 eV-sec); v = photon frequency (Hz)
• Photon or quantum= a small bundle of energy that carries a specific amt of energy that is dependent on frequency.
• Protons and neutrons are responsible for almost all= of the mass of an atom
• Protons have a mass xx times the mass of electrons= 1,836 times
• Q shell= orbital shell farthest away from the nucleus = n=7
• Quantum or wave mechanics= states that orbital electrons are assigned probabilities for occupying any location within the atom. The greatest probabilities are associated with Bohr’s original model.
• Quarks= the smaller subnuclear structures of protons and neutrons
• Radiation= when energy is emitted and transferred through matter – heat, light
• String theory= M theory’s new name.
• The 2 forces that maintains an electron’s position and motion in its orbit= centrifugal force and the attractive electrostatic force
• The 3 subatomic particles= protons (+); neutrons – neutral; electrons (-)
• The amu of a neutron is= 1.00867 amu
• The amu of a proton is= 1.00728 amu
• The amu of an electron is= .000548 amu
• The binding energy of tungsten is 69.5 keV= so it takes energy of 70 keV to remove a tightly bound inner shell electron
• The bottom end of the spectrum contain= low frequencies and long wavelengths like radio waves and microwaves
• The closer an electron is to the nucleus the greater will be the binding energy of the electron – more tightly bound
• The electromagnetic spectrum= a continuum of wide ranges of magnitudes of EM energy with heat at the left, radio/tv/radar/MRI, visible light, infrared, ultraviolet, x-rays, gamma rays, and cosmic rays at the right end.
• The key distinguisher of elements= the number of protons in the nucleus
• The mass of a proton= 1.673 x 10^-27 kg
• The relationship b/w TOTAL energy and principle quantum number is= direct – higher energy shells have higher TOTAL energy
• The relationship between binding energy and principle quatum number is= inverse – higher energy shells have lower binding energy
• The top of the spectrum contain= high frequency and short wavelengths
• Theory of relativity= defined by Albert Einstein in 1905. E=mc²; E – energy; m – mass; c – constant (speed of light in a vacuum)
• Total energy is the combination of= potential energy and binding energy
• Unit of mass= kilogram – 1000 grams
• Valence= chemical combining characteristic – the number of electrons in the outermost shell.
• Velocity formula – wave equation= velocity = frequency x wavelength or c=vy; c = constant (the speed of light); v = the frequency; y = the wavelength
• Velocity= one of the common properties of all EM radiation – equal to 3 x 10 ^8 meters/second. 186,4000 miles per second in a vacuum – the speed of light.
• Wave theory= EM energy travels thru space in the form of waves
• Wavelength=distance b/w any two successive points on a wave – measured crest to crest or trough to trough. Represented by the Greek letter lambda (upside down y). Vary from km to Angstroms. Vary in size from very long radio waves to very short gamma-rays. Measured in Angstroms – xrays are .1 to .5 Angstroms
• Wave-particle duality of radiation=dual nature behavior that occurs with EM radiation – scientists have found that under certain circumstatnces, EM radiation behaved as a wave and at other times, it behaved as a particle. To understand x-rays, they should be considered both as waves and particles of energy.
• Waves have an associated= wavelength, frequency, amplitude and period
• Weight= the force that an object exerts under the influence of gravity
• What determines the energy of a shell= the distance from the nucleus
• When an atom of an element loses or gains a proton, it becomes a= different element (if carbon gains a proton, it becomes nitrogen)
• X-ray tube target materials= tungsten and molybdenum (Mo)
• X-rays are created= in an x-ray tube when high-speed electrons are suddenly stopped. Man-made.
• X-rays are physically identical to=gamma rays, but differ in origin. X-rays are man-made – originating in an x-ray tube, while gamma rays originate from the nucleus of radioactive materials.