Concerning the atom, what is the production of x-ray dependent on?
the interaction of electrons and matter at the anode
What two interactions occur at the atomic level that concern us in the field of x-ray radiation?
the interaction of an x-ray photon and the human body
the interaction of an attenuated x-ray beam and the receptor
Early Greek theory of the atom included:
the four elements: earth, air, fire, water
What did Democritus contribute to atomic theory and when?
Thought matter could not be divided indefinetly, leading to the idea of atoms in a void (also, the four elements)
460 BC to about 370 BC
What did Dalton contribute to atomic theory and when?
all elements are composed of tiny, indivisible, and indestructible particles called atoms
the atoms are unique to each element in their size and mass
compounds are formed by molecules which are formed by fixed ratios of each type of constituent (part of a whole) atom, resulting in predicable mass.
a chemical reaction is a rearrangement of the atom.
discovered scientific evidence recognizing that elements combined to form compounds.
Describe the chain that composes the difference makeups of the structure of matter:
Atoms come together to form molecules.
Molecules combine to form elements.
When one or more elements join chemically, they form compounds.
Substances can be simple (one element) or complex
Two or more substances combined make mixtures.
substances that cannot be separated into simpler substances:
substances formed when two or more elements are chemically joined:
The smallest particles of matter:
An electically neutral group of at least two atoms held together by a covalent bond.
What distinguishes a molecule from an ion?
their electrical charges
What makes the difference between a covalent bond and an ionic bond?
covalent bonds involves the sharing of electrons.
ionic bonds involves the transfer of electrons.
What did J.J. Thomson contribute to atomic theory and when?
discovery of the electron.
discovered electron spectrometer
around 1906 (when he received the Nobel Peace Prize in Physics)
List the differences between:
isotope, isotone, isobar, isomer
isotoPe = the Proton stays the same.
isotoNe = the Neutron stays the same.
isobAr = the Atomic mass number (A#) stays the same.
isomEr = everything stays the same.
What does this image represent?
the "plum pudding" model, describing an atom as a big ball of electrons thrown together as a random, structureless mass, as theorized by Thomson.
Why was Thomson's discoveries about neon isotopes important to our field?
the light emission found by Thomson helped lead Roentgen to the discovery of x-rays.
What did Rutherford contribute to atomic theory?
scattering equipment suggested there were holes in the atom because some alpha particles passed through without interaction while others had varying angles of deflection (due to the interaction with the atom)
this contradicted the plum pudding model by Thomson (Rutherford's teacher).
What did Bohr contribute to atomic theory?
he put forth the modern theory of the atom.
List the components of the atom:
nucleus - a small, dense center containing the nucleons, protons, and neutrons
electrons that orbit the nucleus in defined energy bands or shells
Describe the electrical charges of the parts of the atom:
each proton has one unit of positive charge
each electron has one unit of negative charge
neutrons have no charge
Describe the energy of the shells of the atom:
the K shell has the greatest binding energy. The binding energy decreases with each subsequent shell.
How can the maximum number of electrons that fit onto each shell be determined?
with the formula: 2n2
the "n" represents the shell number, with the K shell always being shell number one (L=2, M=3, and so on)
example: for the K shell: 2x12= 2x1=2. K shell can hold two electrons.
a way of classifying elements based on the number of protons, neutrons, and electrons in each of their constituent atoms:
(the 2nd to last letter in the name of each can be used as a prompt to tell what stays the same)
What makes up the atomic mass (A#)?
the mass of the parts of the nucleus (protons, neutrons).
does NOT include the mass of the electrons
mass of a proton is 1836 times greater and mass of a neutron is 1838 times greater than mass of an electron.
What makes up the atomic number (Z#)?
the number of protons in the nucleus of an atom.
routinely, on the periodic table, the Z# is on top, and the A# is underneath
on the periodic table, higher Z#s grow toward the bottom right, and lower Z#s shrink toward the top left.
What happens when the Z# of an element changes? Give an example.
the element changes.
ex. in radioactive decay, Radium (Z#88) emits an alpha particle and decays to Radon (Z#86)
What happens when the A# of an element changes? Give an example.
Changing the number of neutrons or electrons does NOT change the element.
ex. changing the number of neutrons creates an isotope
ex. changing the number of electrons creates an ion which could create ionization
Describe the two ways in which atoms bond to form molecules:
ionic bond: when one atom gives up an electron and becomes positively charged and another atom takes on that electron, acquiring a negative charge (it is the difference in charge that bond the two atoms together)
covalent bond: when two atoms share electrons that then orbit both nuclei, completing the outermost shell of each
Describe two aspects of the basic organization of the periodic table of elements:
horizontal periods indicate elements that have the same number of electron shells
vertical groups have the same number of electrons in the outer (valence) shell
studies the relationships between matter and energy:
has mass and occupies space:
the force used to do work:
What is the Law of Conservation of Matter and Energy?
Who is credited with the foundation of modern physics?
(quantum physics or wave mechanics)
What are protons and neutrons made up of:
What does the M Theory do?
a.k.a. the String Theory
links quantum physics and relativity
What maintains electrical stability of the atom?
an equal number of protons and electrons
What factor distinquishes an element?
the atomic number (Z#): the number of protons contained in the nucleus
What results when an xray photon interacts with an electron, ejecting it from the atom?
ionization of the atom
What unit is used to measure Electron Binding Energy (Eb)?
electron volts (eV)
What is an electron volt?
the energy of one electron when accelerated by one volt
What is the chemical combining characteristic that describes how an atom will bond with another atom?
the atom's valence
A +1 atom is also called a(n) __________ and it __________ an electron.
A -1 atom is also called a(n) __________ and it __________ an electron.
What is the Octet Rule?
an atom never has more than eight electrons in its outer shell.
An atom with eight electrons in its outer shell is:
chemically stable (inert)
What is the physicist's definition of work?
work = force x distance
(a force acting upon an object over a distance expends energy)
The action of physical movement:
Name the two types of mechanincal energy:
A body converts _________ energy from food into ___________ energy or movement.
A battery converts __________ energy into __________ energy.
What is another name for heat energy?
Results from the movement of molecules:
heat (thermal) energy
What is thermal energy measured by?
A toaster converts ___________ energy into ___________ energy.
Results from the movement of electrons in a conductor:
A light bulb converts _________ energy into _________.
Name the best known conductor, plus two more we discussed:
Name three non-conductors we discussed:
Obtained by breaking the bonds between the particles within a nucleus:
When creating nuclear energy, what is a common by-product?
a lot of heat
Willhelm Roentgen won the Nobel Peace Prize for physics in what year and for what reason?
identified the use of barium platinocyanide
T/F: X-ray is a penetrating and visible form of EM radiation.
False: PENETRATING and INVISIBLE
T/F: X-rays are negatively charged.
False: electrically neutral
T/F: X-rays can be polyenergetic or heterogenous energies.
T/F: X-rays release heat when passing through matter.
T/F: X-rays travel in waves.
False: they travel in straight lines.
T/F: Gamma rays travel at the speed of light, but X-rays do not.
False: x-rays travel at the speed of light, as do all electromagnetic waves.
T/F: X-rays can ionize matter.
T/F: X-rays do not affect photographic film.
False. they do.
T/F: X-rays produce polar and magnetic changes in matter through ionization and excitation.
False: produce CHEMICAL and BIOLOGICAL changes
T/F: X-rays produce secondary and scatter radiation.
T/F: X-rays cause opulence in certain crystals.
False: cause FLUORESCENCE
T/F: X-rays cannot be focused by a lens.
It is the nature of electromagnetic energy that all forms travel at the speed of light and vary only in (3):
In thinking of the rainbow (Roy G. Biv), which end is the lower frequency and which end is the higher frequency?
Violet = higher frequency
Red = lower frequency
List the order of waveforms from lowest frequency to highest frequency:
As you increase the wavelength on the electromagnetic spectrum, the energy will increase or decrease?
As the wavelength on the electromagnectic spectrum decreases, does the frequency increase or decrease?
Give the exact speed of light:
(also shown as 3x108 m/s)
A form of energy that originates from the atom after interaction takes place:
T/F: Electromagnetic radiation requires a medium through which to travel:
False: it does not. it can even travel in a vacuum.
What type of energy is sound?
Offers a relationship mathematically between energy and frequency of electromagnetic radiation:
Planck's Constant (4.15x10-15eV)
Give the formula for calculating energy or frequency when using Planck's constant:
e is energy
h is Planck's constant (4.15x10-15eV)
f is frequency
Who theorized electromagnetic radiation existed as "packets of energy called photons"?
According to Max Planck: as energy increases, frequency will:
As you decrease the frequency on the electromagnetic spectrum, the energy will increase or decrease?
Why does electomagnetic energy not require a medium through which to travel?
it vibrates itself with electricity and magnetism.
Induction allows electricity to induce a ____________. Give an example.
ex. the stator in the X-ray tube
What are the two ways electromagnetic radiation can be exhibited depending on its energy and/or environment?
What is the characteristic of electromagnetic radiation that results in either a wave or a particle form?
wave particle duality
In wave particle duality, is the intensity greater or lesser where the waves cross/join?
Name the velocity of electromagnetic radiation:
(velocity can be described as the speed)
The maximum height of a wave:
Peak of one wave to peak of next wave:
Number of waves that pass a given point per second:
Give the formula to find frequency and/or wavelength of electromagnetic radiation:
c = 3x108 m/s (speed of light)
ƛ = wavelength
f = frequency
Higher energy radiation tends to exhibit more ________ characteristics and lower energy radiation tends to exhibit more ________ characteristics in dealing with wave-particle duality.
particle (ex. gamma acts more particulate)
wave (ex. radio acts more wavelike)
high energy x-ray and gamma exhibit wave characteristics of:
X-ray and Gamma ray can _____________ and ____________ according to the inverse square law, both being particulate characteristics.
X-ray and Gamma can both __________ matter which can cause biological damage.
Where is the generalized area that MRI falls on the electromagnetic spectrum:
between radio and microwave
the basic principle of opertation of MRI hinges on the fact that the nuclei of the __________ atoms are __________.
What happens to the hydrogen atoms of human tissue when placed in a strong magnetic field, such as an MRI?
the nuclei will absorb and reemit radiowaves of a particular frequency
(the receptor receives varying frequencies which represent varying types of tissue being imaged)
What happens to the body when placed in the magnetic field of an MRI?
it becomes polarized.
What energy causes vibration of the atoms and molecules causing them to release excess energy as heat?
What energy is used when sending signals between electronic devices?
Is infrared energy an ionizing energy?
no, but excessive amounts to the cornea of the eye can cause damage
_________ light consists of all the colors of the visible spectrum and ___________ all the colors.
____________ light ________ none of the colors of the visible spectrum but ________ all of them.
__________ light would __________ all of the colors and reflect the wavelength of itself only.
(this is true of all of the other colors of the spectrum except black and white)
Energy that stimulates melanin production in skin cells:
What are two physical particles originating from radioactive atoms with the ability to ionize matter, much like x-rays and gamma rays?
alpha and beta particles
Atoms with excess energy that emit particles from the nucleus to obtain stability:
the process by which a radioactive element gives off excess energy and particles to regain stability:
an element composed of atoms with unstable nuclei:
the length of time it takes for half the remaining atoms in a quantity of a particular radioactive element to decay:
half-life (ex. radium 226 has half-life of 1620 years)
a unit of measurement of radioactive decay:
becquerel or curie
an electron emitted from an unstable nucleus:
Which is lighter, an alpha particle or a beta particle?
T/F Beta particles can have a positive or negative charge.
Two protons combined to two neutrons:
Alpha particles (large compared to beta particles, have a positive charge)
What often happens with alpha particles when passing through air?
they pick up electrons attracted to their positive charge, changing them to a neutral helium
helium: 2 protons, 2 neutrons, 2 electrons
T/F: Due to their size, Alpha particles penetrate easily.
False. Much larger than Beta particles, do NOT penetrate easily.
Unit 1 (Structure of the Atom & EM-Particulate Radiation)
Unit 1. Do not rely solely upon these cards. last revised fall2012.