BME 229 Study Guide - Fall 2018, Comprehensive Midterm Notes - Unified Atomic Mass Unit, Sun, Radiography
12 Oct 2018
School
Department
Course
Professor
BME 229
MIDTERM EXAM
STUDY GUIDE
Fall 2018
1
Basic of Nuclear Physics
Joseph John Thompson
• 1856-1940
• English physicist
• Received Nobel Prize in 1906
• Usually considered the discoverer of the electron
• Worked with the deflection of the cathode rays in an electric field
o Opened up the field of subatomic particles
Eal Models of the Atos, Thoso’s
• J. J. Thomson established the charge to mass ration for electrons
• His model of the atom
o A volume of positive charge
o Electrons embedded throughout the volume
o The atom as a whole would be electrically neutral
Eal Models of the Ato, Ruthefod’s
• Rutherford
o Planetary model
o Based on results of thin foil experiments
o Positive charge is concentrated in the center of the atom, called the nucleus.
o Electrons orbit the nucleus
Niels Bohr
• 1885-1962
• Danish physicist
• Active participant in the early development of quantum mechanics
• Awarded the 1922 Nobel Prize in Physics
o For structure of atoms and the radiation emanating from them
Boh’s Model of Ato,
• The electron moves in circular orbits around the proton under the electric
force of attraction
o The coulomb force produces the centripetal acceleration
Coulo’s La
• Fe = ke
• SI unit of charge: Coulomb (C)
• ke is called the Coulomb constant
o = 8.9876x 109 N*m2/C2 = 1/(4πε0)
Boh’s Model of Ato,
• Only certain electron orbits are stable
o These are called stationary states
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2
o I these oits atos do’t eit eeg i the fo of eletoageti adiatio, ee though the ae
accelerating.
o Therefore, the energy of the atom remains constant and classical mechanics can be used to describe the
eleto’s otio
o This representation claims the centripetally accelerated electron does not continuously emit energy and
therefore does not eventually spiral into the nucleus
Boh’s Model of Ato,
• Radiation is emitted by the atom when the electron makes a transition form a more energetic initial stationary
state to a lower-energy stationary state.
o The transition cannot be treated classically
o The feue eitted i the tasitio is elated to the hage i the ato’s energy
o The frequency of the emitted radiation is given by:
▪ ∆E = Ei – Ef = hf
▪ h is the Plak’s ostat h= 6.66 -34 m2*kg/s)
o If a photon is absorbed, the electron moves to a higher energy level
Milestones in the Development of Nuclear Physics
• 1896: the birth of nuclear physics
o Becquerel discovered radioactivity in uranium compounds
• Rutherford showed radiation had 3 main types:
o Alpha (He nuclei)
o Beta (electrons)
o Gamma (high energy protons)
• 1911: Rutherford, Geiger, and Marsden performed scattering experiments
o Established that the nucleus could be treated as a point mass and a point charge
o Most of the atomic mass was contained in the nucleus
o Nuclear force was a new type of force
Some Properties of Nuclei
• All nuclei are composed of protons and neutrons
o Exception is ordinary hydrogen with a single proton
• Atomic number Z – the number of protons in the nucleus
o Sometimes called the charge number
• Neutron Number N – number of neutrons in the nucleus
• Mass Number A – number of nucleons in the nucleus
o A = Z + N
o Nucleon is a generic term used to refer to either a proton or a neutron
o Mass number is not the same as the mass
Symbolism
• Nuclide – specific combination of atomic number and mass number that represents a nucleus
o
o X is the chemical symbol of the element
More Properties
• The nuclei of all atoms of a particular element must contain the same number of protons
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Document Summary
English physicist: received nobel prize in 1906, usually considered the discoverer of the electron, worked with the deflection of the cathode rays in an electric field, opened up the field of subatomic particles. Ea(cid:396)l(cid:455) models of the ato(cid:373), ruthe(cid:396)fo(cid:396)d"s: rutherford, planetary model, based on results of thin foil experiments, positive charge is concentrated in the center of the atom, called the nucleus, electrons orbit the nucleus. 1885-1962: danish physicist, active participant in the early development of quantum mechanics, awarded the 1922 nobel prize in physics. For structure of atoms and the radiation emanating from them. The electron moves in circular orbits around the proton under the electric force of attraction: the coulomb force produces the centripetal acceleration. Coulo(cid:373)(cid:271)"s la(cid:449: fe = ke(cid:3044)(cid:3117)(cid:3044)(cid:3118)(cid:3045)(cid:3118, si unit of charge: coulomb (c, ke is called the coulomb constant, = 8. 9876x 109 n*m2/c2 = 1/(4 0) Boh(cid:396)"s model of ato(cid:373), (cid:1006: only certain electron orbits are stable, these are called stationary states.
