CHM 1210 1st Edition Lecture 6Outline of Last LectureI. Atoms, Ions and Moleculesa. Navigating the periodic Tableb. The Masses of ions, atoms and moleculesc. Moles and Molar massOutline of Current LectureII. Atoms, Ions and Moleculesa. Big Bang TheoryCurrent Lecture:H and He atoms in stars fuse to form heavier elements. -Atoms are formed through fusion and fission in stellar nucleosynthesis. -Subatomic particles fuse to form H and He nuclei during the primordial Nucleosynthesis___. -Quarks combine with one another to form _neutrons and protons__. -Formation of subatomic particles such as electrons and _quakes_ from the energy released.-Definitions: Quarks = elementary particles that combine to form _neutrons and protons____. Nucleosynthesis = the natural formation of nuclei as a result of Fusion and other nuclear process equations___. Nuclear equations: Obs: Like chemical equations, nuclear equations must also be _balanced_. -mass # (superscript)-charges( subscripts) Obs: - By about 5 min after the Big Bang, the matter of the universe had become 75% _protons bymass_ and 25% __alpha particles__. -Nucleosynthesis then came to a screeching halt. Neither 5Li nor 8Be is a __stables_____ nuclide. ? 42��+ 11� 53��?242�� 84��These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Obs: The combined masses of the four nucleons in helium-4 are Obs: The difference between this value and the actual mass of the 4He nucleus is Nuclear Binding Energies Definitions: -Mass defect (Dm) = the difference between _the mass of a stable nucleus and the mass of the individual neucleons that composes__ -Binding energy (BE) = the energy that holds_the nucleons together in a nucleous____. Obs: The stability of a nucleus is proportional to its BE_ • E = ______________ -Dm = mass defect of the nucleus (in kg). -c = speed of light (2.998 × 108 m/s2) 21 - 6 Let us calculate BE of anα particle based on its mass defect. Obs: -This enormous energy means that 4He is a __stable___ nuclide. -Most of the stable nuclei with larger number of nucleons than 4He have even _larger___binding energies. Definition: Strong nuclear force = the fundamental force of nature that keeps quakes_ together in subatomic particles and__nucleons___ together in atomic nuclei. 21 - 7 Stability of Nuclei -Nuclide stability is proportional to _Binding energy / # of Nucleons___ -56Fe = most _stable_ nucleus Stellar Nucleosynthesis Fusion reactions: -Initially, H nuclei served as the fuel for the star furnaces, and their _fusin_ to form more He nuclei provided the energy. -The high density and temperature (109 K) in stars (red giants) caused additional __fusion reactions__ -to create elements __heavier_ than H and He. -For billion of years, such fusion reactions have simultaneously _fueled_ the nuclear furnaces of stars and produces isotopes as heavy as _iron Fe-56__. -Once the core of a star turns into _Fe-56_, the star is running out of _Fuel_, begins to cool and collapses into itself with a gigantic explosion (supernova). -As a star collapses, compression reheats its core to above 109 K and leads to the disintegration of nuclei into _free protons and neutrons __. -Free neutrons may collide and fuse with atomic nuclei in a process called __neutron capture_. Definition: Neutron capture = the absorption of a __spontaneous- radioactive decay__ by a nucleus. -Example: 5626��+301�2659�� Fission reactions: -Unstable nuclei (neutron-rich) may experience ___alpha particle____ -α-decay -β-decay Definition: Alpha (α) Decay = the nuclear reaction in which an unstable nuclide spontaneously emits an _proton and beta