Physics Chapter 2 Structure of the Atom
4 reasons why the study of atoms is necessary for education and training in radiographic imaging:
1. Interactions in the x-ray tube that produce x-rays 2. Interactions between the x-ray photons and the human body 3. Interactions between the x-ray photons exiting the patient to produce the image interact at the atomic level of the image receptor to generate the final image 4.Electricity
Formula used to determine the maximum amount of electrons a shell can hold:
2n^2 n= shell number (K=1)
Electron shell
A defined energy level at a distance from the nucleus within which electrons orbit; describe a sphere around the nucleus
Binding energy
A force of attraction that holds the nucleus of an atom together and holds electrons in orbit around the nucleus; a measure of the amount of energy necessary to split an atom
Isotope
Elements whose atoms have the same number of protons but a different number of neutrons
All elements are composed of _____________
atoms
The reason for the mass defect is because some mass is converted into ____________________
energy
An atom has defined ______________________ each at different distances from the nucleus
energy levels
Subscript number below chemical symbol
atomic number
Element
A substance that cannot be broken down into simpler parts by ordinary chemical means; the simplest forms of substances that compose matter; made up of one unique type of atom with an unchanging number of protons
Covalent bond
An atomic bond in which an outermost electron from one atom begins to orbit the nucleus of another adjacent atom in addition to its original nucleus; share electrons
These interactions involve attraction to the nucleus of the atom, and the penetrating strength (energy) of the x-ray photon depends on the nuclear binding energy
Bremsstrahlung interactions
_______________________________________ is a rearrangement of atoms
Chemical reaction
___________________________________ is a characteristic of matter, whether it is a subatomic particle, an atom, or a larger object
Electrical charge
The force of attraction between the negatively charged electrons and positively charged protons of the nucleus
Electron binding energy
Isobar
Elements whose atoms have a different number of protons but the same total number of protons and neutrons (atomic mass number)
Isotone
Elements whose atoms have the same number of neutrons but a different number of protons
Isomer
Elements whose atoms have the same number of protons and neutrons but with different amounts of energy within their nuclei ( everything that is all the fundamental particles of the atoms, remains the same)
Molecule
Fixed ratio of each type of constituent atom resulting in a predictable mass; two or more atoms bonded together
2 things electron-binding energy depends on:
How close the electron is to the nucleus How many protons are in the atom (The closer the electron is to the nucleus, the stronger is its binding energy)
How do electrons orbit the nucleus?
In 3 dimension
How are the electrons arranged around the nucleus?
In electron shells labeled K, L, M, N, O, P and so on K being the closest to the nucleus; They fill from the K shell outward with the last shell not necessarily filling completely depending on the stability of the atom
Bonding that is based on the attraction of opposing charges; one of the atoms gives up an electron and the other takes the extra electron the difference in their electrical charge attracts and bonds the two together
Ionic bonding
A way of classifying elements based on number of protons, neutrons, and electrons in each of constituent atoms
Isos
Who discovered the electron? Resulted from the scientific community's fascination with the cathode ray tube which led Dr. Roentgen to his discoveries of x-rays.
Joseph John "J.J" Thomson (Plum Pudding Model)
States that like charges repel each other and opposites attract
Law of Electrostatics
20th-century Danish physicist who refined Rutherford's, bringing us to the theory and model of the atom with which we are most familiar; it is based on the solar system
Niels Bohr
Ionic bond
Occurs when one atom gives up an electron and becomes positively charged and another takes on that electron, acquiring a negative charge and it is the difference in charge that bonds the two together
This rule states that, except for the first (K) shell, a maximum of 8 electrons can exist in the outer most shell of any atom
Octet Rule
What are alpha particles?
Particles that are made up of two protons and 2 neutrons (basically the nucleus of a helium atom) and have a positive charge
Based on mathematics and wave properties, more accurately describes the atom
Quantum Theory
Neutron
Subatomic particle with no electrical charge (neutral)
Electron
Subatomic particle with one unit of negative electrical charge
Proton
Subatomic particle with one unit of positive electrical charge
If a particle strikes the nucleus with the energy equal to the nucleus's binding energy, what could happen?
The atom could break apart
Atom
The basic building block of matter composed of electrons, protons, and neutrons
Nucleus
The central core of an atom made up fundamentally of protons and neutrons
Compound
The combination of elements in definite proportions or bounded together; 2 or more elements; a molecule that contains at least two different elements
What keeps electrons in orbit?
The force of attraction between the negatively charged electrons and positively charged protons (electron-binding energy)
Atomic number
The number of protons an atom contains in its nucleus (Remember that in a stable atom the number of electrons is equal to the number of protons, so this indicates the number of electrons)
Atomic mass number
The number of protons and neutrons an atom has in its nucleus
True or False? Electrons do not all occupy the same orbit at the same distance from the nucleus.
True
An atom that gains an electron and has a net negative electrical charge
anion
Superscript number above chemical symbol
atomic mass number
The bigger the atom the more the ________________________________
binding energy
This energy creates a very strong attraction in the nucleus that overcomes even the natural tendency for like charges to repel
binding energy
7 elements of the periodic table important in radiology:
calcium (Ca), barium (Ba), tungsten (W), aluminum (Al), lead (Pb), oxygen (O), and iodine (I)
An atom that gives up and electron and has a net positive electrical charge
cation
It is the ___________________________ between atoms that allow complex matter (such as living tissue) to exist
chemical bonds
Is an abbreviation of the element
chemical symbol
Particle that is smallest in terms of mass:
electron
The penetrating strength (energy) of the x-ray photon produced depends on the difference in _____________________________ of the electron shells involved
electron binding energies
Atoms in each period of the periodic table have the same number of ______________________________, and they increase as one moves from the top row to the bottom row (the elements become increasingly larger and more complex)
electron shells
Units for electron binding energy:
electron-volts (eV)
In a stable atom the number of __________________________ is equal to the number of protons
electrons
Atoms are mostly made up of ______________________________
empty space
In a covalent bond, an outermost electron from one atom begins to orbit the nucleus of another adjacent atom in addition to its original nucleus creating a __________________________________ as it orbits first one nucleus, then the other
figure eight
The greater the complexity of the atom, the ______________________ the opportunity for interactions to occur
greater
The word atom means____________________________ The Greek term for atom is ________________
indivisible- can't be broken down into anything simpler (atamos)
The electron has very little mass compared with the mass of the nucleus, but each electron moves extremely fast in its orbit, and thus it has significant _______________________________
kinetic energy
All compounds are _________________________, but not all _______________________ are compounds
molecules
If an atom gains an electron it becomes _____________________________
negative and has a negative net charge
If an atom has an equal number of protons and electrons, it is considered _______________________________
neutral; it has no net charge, the positives and negatives are equal and cancel each other out
Both _______________________________ and _______________________________ are key determinates of x-ray production
nuclear binding energy electron binding energy
Protons and neutron are held together in the nucleus by ___________________________________; what is the units for this
nuclear binding energy; MeV
Protons and neutrons are collectively called_______________________
nucleons
Electrons do not all occupy the same _________________________ at the same ______________________________ from the nucleus
orbit distance
In which order are elements arranged on the periodic table?
order of increasing atomic mass
Atoms in each group have the same number of electrons in the ____________________________ shell and increases as one moves from left to right
outermost shell
Another means of classifying elements is according to the ________________________________________
periodic table
The periodic table is organized by ________________________ and _________________________
periods and groups 7 periods arranged as rows 8 groups arranged as columns
Charge of the nucleus of the atom:
positive
If an atom looses an electron it becomes __________________________
positive and has a positive net charge
The __________________ and ________________________ compose the majority of the mass of an atom
protons and neutrons
The atom has a nucleus made up of _________________ and ________________; orbiting the nucleus are ____________________________ in defined energy levels and distances from the nucleus
protons and neutrons electrons
3 fundamental particles that make up the atom:
protons, neutrons, and electrons
Mass of nucleus is always less than the sum of the masses of nucleons that make up the nucleus and this difference in mass is called_______________________________; represents the energy necessary to hold the nucleus together
the mass defect
The quantity of the proton, neutron, and electron is ____________________ to the matter or element it composes
unique