Chem 112 Advanced Inorganic Chemistry PDF

CHEM 112- ADVANCED INORGANIC CHEMISTRY Nuclear Chemistry CHEM 112...

CHEM 112- ADVANCED INORGANIC CHEMISTRY Nuclear Chemistry CHEM 112 A D V A N C E D I N O R GA N I C C H E M I S T R Y NUCLEAR CHEMISTRY P RE PARE D BY: KIMBHIERLY M LUDOVICE IN ST RUCT OR 1 Can metal really be converted into gold? Is there a science behind the Philosopher’s Stone? 2 Galena (PbS) Cerrusite (𝐏𝐛𝐂𝐎𝟑 ) Cerrusite (𝐏𝐛𝐒𝐎𝟒 ) 3 1  CHEM 112- ADVANCED INORGANIC CHEMISTRY Nuclear Chemistry EXPECTATION REALITY 4 atomic number (Z) ATOMIC NUCLEUS mass number (A) isotopes relative atomic mass 5 6 2  CHEM 112- ADVANCED INORGANIC CHEMISTRY Nuclear Chemistry NUCLEAR STABILITY Electrostatic Force - force that causes opposite electrical charges to attract each other Nuclear Force- holds the nucleons of nuclei together NUCLEON ❖ either a proton or a neutron, considered in its role as a component of an atomic nucleus ❖ made of quarks hold by gluons (strong force) 7 ADD ON CONCEPT… A proton’s quarks What is the smallest thing in the universe? A neutron’s quarks 8 A D D O N C O N C E P T … 9 3  CHEM 112- ADVANCED INORGANIC CHEMISTRY Nuclear Chemistry NUCLEAR BINDING ENERGY ❖the minimum energy that is required to disassemble the nucleus of an atom into its constituent protons and neutron. ❖positive number for stable nuclei (negative in theoretical physics) MASS DEFECT ❖the atomic mass of any other atom (except H) is less than the sum of the masses of the protons, neutrons and electrons present Your Mass is NOT From the Higgs Boson ❖ loss in mass and liberation of energy are related by Einstein’s equation (E = m𝑐 2 ) 10 Example: = 1.007825 amu = 18.9984 amu = 1.008665 amu mass of 9 H atoms = mass of 10 neutrons = atomic mass of a 199𝐹 = 18.9984 amu < 19.15708 amu mass defect 11 How does it relate to E = m𝐜𝟐 ? Relativity theory tells us that the loss in mass shows up as energy (heat) given off to the surroundings (exothermic) E = m𝐜 𝟐 12 4  CHEM 112- ADVANCED INORGANIC CHEMISTRY Nuclear Chemistry continued… With the conversion factors: amount of energy needed to decompose the nucleus into separate protons and neutrons 13 continued… In the formation of 1 mole of fluorine nuclei, the energy released is, 14 Plot of nuclear binding energy per nucleon versus mass number. 15 5  CHEM 112- ADVANCED INORGANIC CHEMISTRY Nuclear Chemistry For the Fluorine-19 nucleus, 16 neutron- to-proton ratio (n/p) ❖ For stable atoms of elements having low atomic number, the n/p value is close to 1 ❖ As the atomic number increases, the neutron-to-proton ratios of the stable nuclei become greater than 1. ✓ This deviation at higher atomic numbers arises because a larger number of neutrons is needed to counteract the strong repulsion among the protons and stabilize the nucleus 17 Rules in Predicting Nuclear Stability 1. Nuclei that contain 2, 8, 20, 50, 82, or 126 protons or neutrons are generally more stable than nuclei that do not possess these numbers (magic numbers). Example: There are 10 stable isotopes of tin (Sn) with the atomic number 50 and only 2 stable isotopes of antimony (Sb) with the atomic number 51. 18 6  CHEM 112- ADVANCED INORGANIC CHEMISTRY Nuclear Chemistry Rules in Predicting Nuclear Stability 2. Nuclei with even numbers of both protons and neutrons are generally more stable than those with odd numbers of these particles Number of Stable Isotopes with Even and Odd Number of Protons and Neutrons 19 Rules in Predicting Nuclear Stability 3. All isotopes of the elements with atomic numbers higher than 83 are radioactive. Examples: All isotopes of technetium (Tc, Z = 43) and promethium (Pm, Z = 61) are radioactive. 20 Above the belt of stability : nuclei lower n/p ratio Belt of stability through 𝜷-particle emission Below the belt of stability: nuclei increase n/p ratio either by emission of positron or electron capture Plot of neutrons versus protons for various stable isotopes and the type of Decay 21 7  CHEM 112- ADVANCED INORGANIC CHEMISTRY Nuclear Chemistry RADIATION ❖ ENERGY THAT COMES FROM A SOURCE AND TRAVELS THROUGH SPACE AT THE SPEED OF LIGHT ❖ HAS AN ELECTRIC FIELD AND A MAGNETIC FIELD ASSOCIATE D WITH IT AND HAS WAVE- LIKE PROPERTIE S ❖ “ELECTR O MAG NE TI C WAVES”. 22 RADIOACTIVITY ❖the process by which a nucleus of an unstable atom loses energy by emitting particles of ionizing radiation ❖spontaneous emission of particles and/or radiation RADIOACTIVE DECAY SERIES ❖a sequence of nuclear reactions that ultimately result in the formation of a stable isotope 23 The Uranium Decay Series* Parent- beginning radioactive isotope Daughter -product *The times denote the half-lives. 24 8  CHEM 112- ADVANCED INORGANIC CHEMISTRY Nuclear Chemistry NUCLEAR TRANSMUTATION ❖results from the bombardment of nuclei by neutrons, protons, or other nuclei 25 CHEMICAL REACTIONS VS NUCLEAR REACTIONS Chemical Reactions Nuclear Reactions Atoms are rearranged by the breaking and Elements (or isotopes of the same forming of chemical bonds elements) are converted from one to another. Only electrons in atomic or molecular Protons, neutrons, electrons, and other orbitals are involved in the breaking and elementary particles may be involved forming of bonds Reactions are accompanied by absorption Reactions are accompanied by absorption or release of relatively small amounts of or release of tremendous amounts of energy energy. Rates of reaction are influenced by Rates of reaction normally are not affected temperature, pressure, concentration, and by temperature, pressure, and catalysts. catalysis 26 Assignment 1. Differentiate fusion and fission. 2. Enumerate the types and give examples of radioactive radiations? 3. Study balancing nuclear equations 4. Prepare for nuclear-related problem solving 5. List, as many as you can, the advantages and disadvantages of using nuclear technology. 6. Do you agree with the use of nuclear energy as a source of electricity in the Philippines? Why? 27 9