1.3 The Atomic Structure_Nuclear Processes.pdf

ME165-2 ME165-2 Nuclear and Geothermal Energy Mapúa Institute of Technology at Laguna CENTRALIZED COURSE CONTENT AND CONSTRUCTION 1.3 The Atomic Structure...

ME165-2 ME165-2 Nuclear and Geothermal Energy Mapúa Institute of Technology at Laguna CENTRALIZED COURSE CONTENT AND CONSTRUCTION 1.3 The Atomic Structure & Nuclear Energy Processes (Chemical & Nuclear Reactions) Prepared by Engr. Estelito V. Mamuyac 22 August 2024  ATOM – BASIC UNIT OF MATTER The word “atom” is derived from the Greek word “atomos” which means indivisible – the concept of which was first proposed by the Greek philosopher Democritus around 400 BC.  ATOM – BASIC UNIT OF MATTER The atom was thought that it was already the smallest particle and that it can never be divided until the discovery of electron changed the idea and resulted to the discovery of other John Dalton verified the existence of atoms in his ATOMIC THEORY. subatomic particles.  NUCLEAR ENERGY Energy converted using a small amount of mass from splitting an atom’s nucleus which is surrounded by a large amount of mass in a cloud of electrons. 𝑬=𝑴× 𝑪𝟐 where E = energy, M = small amount of mass, C = speed of light  NUCLEAR POWER Heat energy released from a nuclear reactor that is used to produce steam and generate electricity using conventional electrical equipment.  NUCLEAR ENERGY AS RENEWABLE SOURCE ▪ Low carbon emission ▪ Indefinite exploitation period More energy generation with less uranium consumption Uranium deposits on Earth can sustain energy generation for billions of years ▪ Indirect fuel resource from waste ATOMIC MASS NUMBER AND ATOMIC NUMBER 𝐴 85 𝑃 𝑋 36 𝐾𝑟 Where: A = atomic mass number = protons + neutrons P = atomic number = protons A A XP ; XP ; P X A ; A XP Example: 85Kr36  BOARD WORK #1: BW 1-1 Atomic Number Elements Mass number Number of Number of (A) protons (P) neutrons 6 3 Li 14 6C 12 6C 16 8O 235 92U  RADIUS OF NUCLEUS 𝟏 𝑹 = 𝑹𝒐 × 𝑨𝟑 Where: 𝑅 = radius of nucleus 𝑅𝑜 = constant of proportionality = 1.2 x 10-15 m A = atomic mass number  MASS OF NUCLEUS 𝒎𝒏 = 𝑨 × 𝒖 Where: 𝑚𝑛 = mass of nucleus A = atomic mass number 𝑢 = atomic mass unit constant = 1.66053904 x 10-27 kg  DENSITY OF NUCLEUS 𝒎𝒏 𝑨 × 𝒖 𝝆𝒏 = = 𝟑 𝒗𝒏 𝟒𝝅𝑹 𝟑 Where: 𝜌𝑛 = density of nucleus A = atomic mass number 𝑚𝑛 = mass of nucleus 𝑢 = constant = 1.66053873x10-27 kg 𝑣𝑛 = volume of nucleus R = radius of nucleus COMPOSITION OF AN ATOM  COMPOSITION OF AN ATOM An atom is composed of a nucleus surrounded by an electron cloud. The nucleus consists of a collection of neutrally-charged particles called neutrons and positively-charged particles called protons. Protons and neutrons are called nucleons. The negative charged particle; that when orbits around the outermost shell of an atom is called valence electron.  SUBATOMIC PARTICLES Subatomic particle, also called elementary particle, any of various self-contained units of matter or energy that are the fundamental constituents of all matter. Subatomic particles include electrons, and neutrons. But these basic atomic components are by no means the only known subatomic particles. Protons and neutrons, for instance, are themselves made up of elementary particles called quarks, and the electron is only one member of a class of elementary particles that also includes the muon and the neutrino.  SUBATOMIC PARTICLES More-unusual subatomic particles—such as the positron, the antimatter counterpart of the electron—have been detected and characterized in cosmic-ray interactions in the Earth’s atmosphere. The field of subatomic particles has expanded dramatically with the construction of powerful particle accelerators to study high-energy collisions of electrons, protons, and other particles with matter. As particles collide at high energy, the collision energy becomes available for the creation of subatomic particles such as mesons and hyperons.  SUBATOMIC PARTICLES Finally, completing the revolution that began in the early 20th century with theories of the equivalence of matter and energy, the study of subatomic particles has been transformed by the discovery that the actions of forces are due to the exchange of “force” particles such as photons and gluons. More than 200 subatomic particles have been detected—most of them highly unstable, existing for less than a millionth of a second— as a result of collisions produced in cosmic-ray reactions or particle- accelerator experiments. SUBATOMIC PARTICLES  SUBATOMIC PARTICLES Assignment-2: AS 1-2 Find the definitions of the following: Quarks Muons Neutrinos Positrons Mesons Hyperons  ATOMIC MASS UNIT Atomic Sub- Atomic mass unit particles (amu) Neutron 1.008665 Proton 1.007277 Electron 0.0005486 1 amu = 1.66053904 x 10-27 kg  NUCLEAR PERIODIC TABLE  Isotopes are variants of a particular chemical element such that, while all isotopes of a given element share the same number of protons and electrons, each isotope differs from the others in its number of neutrons.  The term isotope is formed from the Greek roots isos ("equal") and topos ("place"), meaning "the same place".  Thus, different isotopes of a single element occupy the same position on the periodic table.  NUCLEAR PERIODIC TABLE  The number of protons within the atom's nucleus uniquely identifies an element, but a given element may in principle have any number of neutrons.  The number of nucleons (protons and neutrons) in the nucleus is the mass number, and each isotope of a given element has a different mass number.  For example, carbon-12, carbon-13 and carbon-14 are three isotopes of the element carbon with mass numbers 12, 13 and 14 respectively.  The atomic number of carbon is 6, which means that every carbon atom has 6 protons, so that the neutron numbers of these isotopes are 6, 7 and 8 respectively.  NUCLEAR PERIODIC TABLE  A nuclear isomer is a metastable state of an atomic nucleus caused by the excitation of one or more of its nucleons (protons or neutrons).  "Metastable" refers to the fact that these excited states have half- lives more than 100 to 1000 times the half-lives of the excited nuclear states that decay with a "prompt" half life (ordinarily on the order of 10−12 seconds).  As a result, the term "metastable" is usually restricted to refer to isomers with half-lives of 10−9 seconds or longer.  Some sources recommend 5 × 10−9 s to distinguish the metastable half life from the normal "prompt" gamma emission half life.  NUCLEAR PERIODIC TABLE  Radioactive isotope  Radioactive isotope or radioisotope, natural or artificially created isotope of a chemical element having an unstable nucleus that decays, emitting alpha, beta, or gamma rays until stability is reached.  The stable end product is a nonradioactive isotope of another element, i.e., Radium-226 decays finally to Lead-206.  Since minute traces of radioactive isotopes can be sensitively detected by means of the Geiger counter and other methods, they have various uses in medical therapy, diagnosis, and research. In therapy, they are used to kill or inhibit specific malfunctioning cells.  Stable isotopes  Stable isotopes are chemical isotopes that are not radioactive - that is, they do not spontaneously undergo radioactive decay. NUCLEAR ENERGY PROCESS  CHEMICAL AND NUCLEAR REACTIONS ▪ Endothermic Reaction – reaction that absorbs energy. There is an increase of mass in the products. ▪ Exothermic Reaction – reaction that releases energy. There is a decrease of mass in the products  CHEMICAL REACTIONS ▪ Synthesis: C + O2 CO2 ▪ Decomposition: 2H2O 2 H2 + O2 ▪ Simple Replacement: Fe + CuSO4 FeSO4 + Cu ▪ Double Replacement: 2KOH + H2SO4 K2SO4 + 2H2O  NUCLEAR REACTIONS Types of Nuclear Reactions: 235 + n1 92 141 + 3(0n1) + MeV Nuclear Fission: 92U 0 ===> 36Kr + 56Ba Nuclear Fusion: H 2 + H2 ===> H3 + H1 + MeV 1 1 1 1 Radioactive Decay: 226 Ra → 4 He + 222 Rn 88 2 86 Nuclear Chain Reaction:  NUCLEAR REACTIONS Types of Nuclear Reactions: Nuclear Chain Reaction:  NUCLEAR REACTIONS If K, L, M and N were chemical symbols, the corresponding nuclear reaction would look like KA1 + LA2 ===> M A3 + NA4 P1 P2 P3 P4 Where, P=number of protons A= mass number To balance, the following relationships must be satisfied P1 + P2 = P3 + P4 A1 + A2 = A3 + A4  NUCLEAR REACTIONS (SAMPLE PROBLEM) Write the complete reaction of 13Al27 + 2He4---> 14 Si 30 + XA4 P4 Solution: Balancing gives, P4 = 13 + 2 – 14 = 1 A4 = 27 + 4 – 30 = 1 The complete reaction is 13Al27+ 2He4 ---> 14 Si 30+ H1 1  NUCLEAR REACTIONS Calculate the change in mass of 13Al27 + 2He4---> 14 Si 30 + H1 1 Reactants Products Al27 26.9815 amu Si30 29.9738 amu He4 4.0003 amu H1 1.0078 amu Total 30.9818 amu Total 30.9816 amu ∆m = Total MassProducts – Total MassReactants  NUCLEAR REACTIONS Calculate the change in mass of 13Al27 + 2He4---> 14 Si 30 + H1 1 Solution: ∆m = Total MassProducts – Total MassReactants = 30.9816 – 30.9818 = -0.0002 amu *Therefore, an EXOTHERMIC REACTION.  BOARD WORK #2: BW 1-2 Write the complete reaction of 7N14 + 2He4---> 8O17 + P4XA4 And calculate for the change in mass and determine if the reaction was endothermic or exothermic. Reactants Products N14 14.0031 amu O17 16.9991 amu He4 4.0003 amu XA4  SYMBOLS The symbol for Uranium-238 : 238 U 92 This shows that Uranium has a mass number of 238 and an atomic number of 92. Symbols are also utilized to represent alpha decay and beta decay particles. o The symbol for an alpha decay particle : 4 He 2 o The symbol for a beta particle is : 0 e-1 o The chemical symbol for a neutron : 1 n0 o The chemical symbol for gamma emission: 0 0 o The chemical symbol for positron emission particle: 0 e+1  ISOTOPIC COMPOSITION AND ABUNDANCE  Most of the elements exist in nature with two or more allowable combinations of nucleons as isotopes of each element.  The isotopic composition (P, N) is determined by the mass number of the isotope (A = P + N). Other isotopes of the elements can be produced artificially by high- energy machines; most of these isotopes are radioactive.  The isotopic abundance (f) of the isotopes in each element in the periodic table is expressed as the fraction found in the natural element.  Twenty of the elements (e.g., sodium (P = 1, N = 12) exist with only one isotope (23Na); for these elements, the isotopic abundance of the one natural isotope is f=1.000.  ISOTOPIC COMPOSITION AND ABUNDANCE  Hydrogen, atomic number 1 in the periodic table, has one proton in the nucleus, but the element hydrogen (P = 1) exists in nature with three isotopic composition: N = 0 1H Normal hydrogen Stable= Hydrogen f = 0.99+ N = 1 2H Heavy hydrogen Stable= Deuterium f =