RJAV 2022 General Chemistry PDF

MODULE 1 CHEM 1 GENERAL CHEMISTRY I. MATTER Mass + Volume STATES SOLID Shape Definite *noncompressible Volume Molecular motion Chemical compounds always contain the exact proportion of element in fixed ratio (by mass) Ex. H2 , C6H12O6 = CH2O LIQUID Indefinite GAS *assumes container shape Vibration D...

MODULE 1 CHEM 1 GENERAL CHEMISTRY I. MATTER Mass + Volume STATES SOLID Shape Definite *noncompressible Volume Molecular motion Chemical compounds always contain the exact proportion of element in fixed ratio (by mass) Ex. H2 , C6H12O6 = CH2O LIQUID Indefinite GAS *assumes container shape Vibration Definite Gliding *ex. *2 stones water falls Indefinite *compressible 3. Law of Multiple Proportion John Dalton When 2 elements form more than 1 compounds, it can be expressed in a fixed whole number (by mass) Constant random Plasma/ Ionized Gas 4th state; most abundant state of matter. Has p+ and e- (thus, greatly affected by magnetic field) Ex. ionized Ne light, Aurora, Stars, Sun C = 12g/mole O = 16g/mole 4. Law of combining weights Proportions by weight when chemical reaction takes place can be expressed in small integral unit Mg = 24g/mole (60%); O = 16g/mole (40%) Enthalpy (heat/ reaction energy): P > G > L > S III. ATOMIC STRUCTURE A. PHASE CHANGE Melting *aka: Fusion, Liquefaction, Thawing 1. Democritus (Liquid to Solid) Evaporation (Liquid to Gas) Condensation (Gas to Liquid) Sublimation *moth/naphthalene balls (Solid to Gas) Deposition *dry ice/ cardice (Gas to Solid) Recombination *aka: Deionization (Plasma to Gas) Ionization (Gas to Plasma) B. MATTER CLASSIFICATION 1. Pure substance Element simplest form of substance. Compound 2 or more chemical united (separated via chemical means) 2. Mixture 2 or more substance wherein individual substance identifies are retained (separated via physical means. Alcohol + Water via distillation) Homogeneous 1 phase; solution *clear colored Heterogeneous 2 phases; suspension, colloid *ex. milk C. CLASSIFICATION BASED ON DEPENDENT TO THE AMOUNT OF MATTER PRESENT 1. Extrinsic Property Length, mass/weight, volume, pressure, entropy, enthalpy, electrical resistance 2. Intrinsic Property Density/ SpGr (water = 1g/ml or cc), viscosity (resistance to flow), velocity (m/sec), temperature, color II. FUNDAMENTAL CHEMISTRY LAWS 1. Law of Conservation of Mass/ Matter Antoine Lavoiser Mass/ Matter is always constant (neither created nor destroyed) Module 1 General Chemistry Atomos (Solid to Liquid) Freezing 2. Law of Definite/ Constant Proportions 2 Joseph Proust 2. John Dalton Billiard ball Matter is made up of atoms Postulates: Elements are composed of indivisible, indestructible atoms Atoms alike for a given element (isotopes) Atoms of different elements differ in size, mass & other properties (isobars) Compound are formed form 2 or more atoms at different elements Atoms combined in simple numerical ratios to form compounds 4. J.J. Thompson Plum Pudding/ Raisin bread e- in (+) framework 5. Ernest Rutherford (discoverer of proton) Nuclear (Gold foil/ scattering experiment) atom is mostly empty; (+) particles in nucleus 6. Neil Bohr Planetary mostly used 7. Erwin Schrodinger Quantum/ Mechanical/ e- cloud Modern atomic Model; estimates the probability of finding an e- in certain position (i.e. at e-cloud/ orbital) Atoms Proton (+) ion Atomic number (basis of electronic configuration) Ernest Rutherford Electrons (-) ion p+ in uncharged state negligible weight 1,836x lighter that p+ J.J. Thompson Cathode ray tube: e- m/2 ratio R.A. Millikan Oil drop experiment: measure accurate charge and mass of eNeutrons no charge Atomic mass (Nucleon) = p+ + n0 James Chadwick # p+ = Atomic # = 11 # n0 = Atomic mass p+ = 23-11 = 12 # e- = p+ in uncharged stated: 11-1 = 10 P #p = 15 #n = 16 #e = 18 Page 1 of 8 RJAV 2022 Find: Atomic no. = 15 Atomic mass = 15 + 16 = 31 Charge = 15 18 = -3 Eugene Gold Stein discovered anode rays Electrochemistry particle separation based on eEx: Capillary electrophoresis separation of compounds based on electrophoretic mobility Electrode: Charge: Undergoes: Anode + electrode Oxidation 4A 6A Ionic bonding Cathode - electrode Reduction RED CAT ELECT IN REDuction happens in CAThode where ELECTrons get IN VILEORA Valence Increase, Loses e-, undergoes Oxidation, Reducing agent VDGEROA Valence Decrease, Gains e-, undergoes Reduction, Oxidizing agent (KMnO4-, Na2Cr2O7) Isotopes same p+/atomic number/ element differ in atomic mass Non-isotopes: 19F, 127I, 31P, etc. Main isotopes: +1: 1H, 12C, 14N, 32S, 35Cl ; +2: 16O, 79Br Isobars same atomic mass differ in elements Isomers same molecular formula differ in structure 1A Valence shell electron pair repulsion (VSEPR) theory Predicts the geometry of the molecule as well as any bonded and unbonded electron pair Linear - CO2 Alkynes (Sp) Trigonal planar Alkenes (Sp2) - BF3 Tetrahedral/bent Alkanes (Sp3) - CCl4 , H2O * 2 bonded pair, 2 unbonded pair IV. CHEMICAL BONDS Molecule aggregate of 2 or more atoms in definite arrangement held together by chemical bonds Ions with net (+) or (-) charge Empirical formula simplest whole number ratio (might be same with MF). Ex: CH2O vs. C6H12O6 Trigonal bipyramid - PF5 A. FORCES OF ATTRACTION Intermolecular FA/ Van der Waals/ Electrostatic Between molecule; weak and short-lived uncharged atoms (n0) approach very closely H-bonding Keesom orientation (D-D) > Water Water Strongest IFA H + S, O, N, X (electronegative atoms) Dipole (D) Polar Induced Dipole (ID) Debye Induction (D-ID) > Water Benzene Octahedral - SF5 London Dispersion (ID-ID) Weakest IFA Aromatics (Benzene Benzene) Nonpolar Intramolecular FA Within molecule Covalent Ionic Sharing of eTransfer of eNonmetal + Nonmetal Metal + Nonmetal (Glycosidic & Peptide bond) (NaCl) Glycosidic ether bond Peptide bond Covalent Bonding Lone pair Pair of valence electrons that are not shared with another atom in covalent bond Module 1 General Chemistry Dashed line away Wedged line toward Trigonal and Octahedral are exemption to the octet rule Valence bond theory States that bonds are formed by sharing of electron from overlapping atomic orbitals (covalent) s = spherical (sigma bond stronger bond formed; headways overlap) p = dumbbell (pi bond weaker; sideways overlap) Page 2 of 8 RJAV 2022 Molecular orbital theory States that bonds are formed from interaction of atomic orbitals from molecular orbitals B. Multivalent (with variable charges) +1, +2 = Hg, Cu +1, +3 = Au +2, +3 = Fe, Co, Ni +3, +5 = Bi, Sb F. POLYATOMIC IONS Bonding lower energy (stable) Antibonding higher energy (unstable) B. REACTION TYPES Synthesis/ Combination/ Direct Union A+B AB Decomposition/ Analysis AB A+B i.e. Complete combustion: CH4 O2 CO2 + H2O Incomplete combustion: CH4O2 CO + C(5) + H2O A. O-containing polyatomic anions (Oxyanions) Oxyanions Salt Oxyacid (Aq) ClOHypochlorite Hypochlorous acid (HClO) ClO2Chlorite Chlorous acid (HClO2) ClO3Chlorate Chloric acid (HClO3) ClO4Perchlorate Perchloric acid (HClO4) NO2Nitrite Nitrous acid (HNO2) NO3Nitrate Nitric acid (HNO3) SO32Sulfite Sulfurous acid (H2SO3) SO42Sulfate Sulfuric acid (H2SO4) PO43Phosphate Phosphoric acid (H3PO4) ate: common form ite: -1 O to ate form hypo -1 O to ite form ate form B. H-containing polyatomic anions Monohydrogen/ bi: with 1H+ ions Dihydrogen: with 2H+ ions Anion Salt HCO3Bicarbonate (Hydrogen carbonate) HSO3Bisulfite HSO4Bisulfate HPO4-2 Biphosphate H2PO4-1 Dihydrogen phosphate G. MOLE RELATIONSHIPS Single Displacement AB + X AX + B Double Displacement/ Metathesis/ Exchange AB + CD AC + BD i.e. Neutralization: NaOH + HCl NaCl + H2O Precipitation: AgNO3 + NaCl AgCl2 + NaNO3 AgCl2 1 mole = 6.022 x 1023 atoms/ molecules Ex. Calculate the no. of NaOH atoms 20g, MW = 40/mol) white curdy ppt. C. REACTIVITY SERIES Metals Li > K > Ba > Ca > Na > Mg > Al > Mn > Zn > Cr > Fe > Cd > Co > Ni > Sn > Pb > H2 > Cu > Ag > Hg > Pt > Au Nonmetals (bases on electronegativity) F > Cl > Br > I Examples: Co + MgCl2 Zn + CuSO4 4 + Cu NaBr + Cl2 D. NOMENCLATURE OF INORGANIC COMPOUNDS 1. Covalent compounds CO: Carbon monoxide SiO2: Silicon dioxide N2O: Dinitrogen monoxide CCl4: Carbon tetrachloride 2. Ionic compounds Ex: Pb(NO3)4 Classical: Plumbic nitrate Stock: Lead(IV) nitrate E. MONOATOMIC IONS Ans = 3.011 x 1023 atoms Molarity/ Formality (M) 3N HCl or 3K HCl Molality (m) Normality (N) Factor (f) Acid (H): HCl = 1; H2SO4 = 2 Base (OH): Al(OH)3 = 3 Salt (M): Al2O3 = Al: 3x2 = 6; Na2SO4 = 2 V. ELECTRONIC CONFIGURATION Aufbau Principle Atoms may be built by progressive filling of energy of main energy sub level (i.e., levels of lower energy levels are occupied first) s=2, p=6, d=10, f=14 A. Monovalent +1 = Group 1 (H, Li, Na, K Ag) +2 = Group 2 (Be, Mg, Ca, Sr, Ba Zn, Cd) -2 = Group 6A (Oxide, Sulfide) -1 = Group 7A (Fluoride, Chloride, Bromide, Iodide) Module 1 General Chemistry Page 3 of 8 RJAV 2022 Ex. Calcium = Atomic # 20; Atomic mass 40 1s2 2s2 2p6 3s6 4s2 [Argon] 4s2 Quantum theories No 2 e- Shortcut He = 2 Ne = 10 Ar = 18 Kr = 36 Xe = 54 Rn = 86 Noble gas: 2. velocity (position & momentum) Orbitals are filled up singly before pairing up Most stable arrangement of e- in subshells is the one with greatest no. of parallel spins. VI. GAS LAWS Boyle's/Mariotte P = Temperature (in K) Charles = Pressure (in atm) Gay-Lussac's = Volume (in L) Combined = A. QUANTUM NUMBERS Principal Quantum Number (n = 1 to 7) main energy level; size of orbital (electron cloud), distance of efrom nucleus Ex. O2 = 1s2. 2s2. 2p4 (n=2) Azimuthal/ Angular Momentum ( = 0 to 3) Angular momentum & shape of orbital; subshell Ideal = R = 0.08205 At STP T = 273.15 K P = 1 atm V = 22.4 L dumbbell shape) Ex. O2 = = 1 Magnetic Quantum Number (m = - , 0, + ) Orientation of orbital in space Ex. O2 = m = -1, 0, +1 Equal volumes of different gases have same no. of moles at STP = = k = 6.022 X 1023 Partial Pressures Total pressure in a mixture (non-interacting gases) is equal to the sum of the partial pressures of each gas. = 1 + 2 + 3 -1,0,+1 [3 degenarate orbitals] = same energy levels -2,-1,0,+1,+2 [5 DO] -3,-2,-1, 0, +1,+2,+3 [7 DO] Rate of effusion (diffusion) and speed gas are inversely proportional to the square root of their density providing the temperature and pressure are same for 2 gases Diffusion rate at which 2 gases mix Effusion rate at which gas escapes through a pinhole vacuum. Rate Magnetic Spin (ms = + ½ , - ½ ) Magnetic moment/ Rotation Spin counterclockwise = - ½ Ex. Oxygen = ms= + ½ n m st Law Diffusion rate (flux) of liquid or gas is directly proportional to the concentration gradient (ftom high concentration to low concentration) ms 1 0=s 0 2 0,1 = p -1,0,+1 3 0,1,2 = d -2,-1,0,+1,+2 4 0,1,2,3 = f -3,-2,-1, 0, +1,+2,+3 Decrease temperature, Increase Pressure (i.e., sealed container), more CO2 is dissolved in water. Real/Van der Waals an2 = internal pressure per mole nb = incompressibility Magnetism types: o Diagmagnetism o Paramagnetism Module 1 General Chemistry no unpaired eat least 1 unpaired e- = X = mole fraction Temperature Page 4 of 8 RJAV 2022 A. TEMPERATURE °C = (°F 32) / 1.8 °F = (°C x 1.8) + 32 K = °C + 273.15 Absolute temperature 0K = absolute zero (lowest possible temperature) VII. SOLUTION Solute + Solvent Colligative properties (See Physical Pharmacy) Dependent on the amount of solute present in the solution Vapor pressure lowering Boiling point elevation (Ebullition) Freezing point depression Osmotic pressure ( ) Vapor Pressure Lowering Entropy ( S) = temperature; degree of disorderliness or randomness S = (+) spontaneous; increase (irreversible) real case S = (-) non spontaneous; constant (reversible) ideal case (in a steady state/ equilibrium) H does not predict spontaneity 3RD LAW: If an object reaches absolute zero temperature (0 K = -273.15 = -459.67 °) Entropy of perfect, solid, crystalline substance is zero at absolute 0 temperature G) Thermodynamic state function that combines enthalpy and entropy G= T S G < 0 (-) spontaneous G > 0 (+) non spontaneous G=0 equilibrium (no more work to be done) Raoult's Law : vapor pressure of a solution is dependent on the amount of nonvolatile solute added to solution IX. CHEMICAL KINETICS Study of reaction rates and reaction mechanism Boiling Point Elevation Freezing Point Depression Osmotic Pressure ( ) - pressure needed to stop osmosis Reaction Rate (M/s) Change in concentration of a reactant or product concentration with time aA + bB cC + dD *small letters: coefficient that balance the chemical reaction VIII. THERMODYNAMICS Study of energy conversion/ transformation in the universe A. PARTS OF THE UNIVERSE A. System Open System - allows exchange of energy and matter Closed System - allows exchange of energy but not matter\ Isolated System "Adiabatic Walls" - does not allow exchange of both energy and matter B. Surrounding everything outside the system B. PATH DEPENDENCE State Function Independent (depends only on initial & final states of system) Entropy (S) Non-State Function Dependent Work and Heat Zeroth Law If two systems are in thermal equilibrium respectively with a third system, they must be in thermal equilibrium with each other a=c b=c a=b C. LAWS OF THERMODYNAMICS 1ST LAW: Law of conservation of Energy Energy is neither created nor destroyed but can be transformed from one form to another Enthalpy (H) = U, P, V Hess' Law: H is independent of reaction/steps that occurred (only the initial and final steps is the basis) q = Heat H = (+) heat is absorbed; COLD (endothermic) H = (-) heat is released; HOT (exothermic) 2ND LAW: Law of Entropy No way but UP For an isolated system, Total entropy can never decrease over time Module 1 General Chemistry Rate Law Expresses relationship of the rate of reaction to the rate constant (K) and concentration of reactants raised to some power aA + bB cC + dD Rate = K [A]x [B]y (xy=order of reaction) Where x & y = order of reaction (0th, 1st, or 2nd) A. REACTION RATE THEORIES 1. Collision Theory rate of chemical reaction is proportional to the number of collisions per time Requirements for effective collision: Proper orientation Activation energy (Ea) minimum amount of energy required to initiate chemical reaction 2. Transition Theory (Formation of Intermediate Complex) - rate depends on Ea required to form intermediate state (where new bonds are formed and old bonds are broken) B. FACTORS AFFECTING REACTION RATE (Directly proportional) Nature of Reactants = reactivity reaction rate (faster) Concentration of Reactants (except Zero order) = concentration reaction rate Catalyst (Enzyme Michaelis Menten Kinetics) = reaction rate Enzymes speeds up the chemical reaction by lowering Ea Surface Area = SA reaction rate Temperature = Temp Arrhenius Equation (T, Ea, RR) reaction rate; X. CHEMICAL EQUILIBRIUM aA + bB Page 5 of 8 cC + dD RJAV 2022 A. LAW OF MASS ACTION reaction rate proportional to the product of the concentrate of the reactants to the power of its coefficient in a balanced equation Acids & Bases Ionic radius Oxidation states Polarizability Electronegativity Ex. Keq = 1: No shift (in equilibrium) Keq > 1: Favors product formation (to the right/ forward reaction) Keq < 1: Favors reactant formation (to the left/ backward or reverse reaction) Le Chatelier Principle (# stress reliever) If an external stress is applied to a system at equilibrium, the system adjusts in such a way that stress is partially offset as the system reaches new equilibrium External Stressors: Equilibrium shift Concentration Pressure & Volume (For Gases only) Yes Change Equilibrium constant (Kc) - 25°C No with lesser gas moles Yes No OH-, F-, Cl-, CO32-, CH3COO- H- (Hydride), I-, SCN- A. ACID-BASE FORMULA Acids & Bases General formula pH = -log[H+] pOH = -log[OH-] pH + pOH = 14 Kw = [H+][OH-] = 1x10-14 *pKa is constant, while pH varies [] M Ionic equilibria For Weak Acids & Bases (with constant) pKa = -log[ka] pKb = -log[kb] pKa + pKb = 14 Kw = Ka x Kb = 1x10-14 Ionic equilibria Conjugate Base = -1H+ to subs in question Conjugate Acid = +1H+ to subs in question Yes Catalyst Yes No No XI. ACIDS AND BASES Acids Taste pH + Litmus paper + Metals In writing Equilibrium constants: Aq. & gaseous reacting spp. (constant: S & L) Unit should be in M Common ion effect Bases Sour 7 Blue - Addition of compound having an ion in common with the dissolved substance will result to: Equilibrium shift (either to the left or right) Suppressed ionization of the dissolved substance (WA or WB) pH change Ex. CH3COOH CH3 CH3 ionization - (effervescence) (Saponification) - Theories Acid Arrhenius Liberates H+ Bronsted-Lowry Donates p+ Lewis e- pair acceptor Lewis Theory: acid/ Electrophile e- loving (+) iron or metal (e- poor spp.) Ex. Manuf NaOH Hard soap KOH Soft soap Base Liberates OHAccepts p+ e- pair donor Ni + CO Cl- + SnCl4 acid (+) Ni SnCl4 Henderson-Hasselbalch/ Buffer pair equation For buffer solutions (WA + CB or WB + CA) HAc + AcNH3 + NH4+ Weak acids Hard-Soft/ Soft-Hard Thermodynamically Weaker interaction General Chemistry = + Weak bases = + *pH = pKa (@ half neutralization point) base (-) CO Cl- Van slyke Buffer capacity Bmax (degree or magnitude of capability to resist change in pH of the buffer) Pearson's Hard and Soft Acid and Base (HSAB) Hard-Hard/ Soft-Soft same Thermodynamically Stronger interaction Hard Acid + Hard Base Ionic complexes Soft Acid + Soft Base Covalent complex CH3COONa Mixture + (aq) + CH3COO- (aq) + (aq) + CH3COO- (aq) - suppressed Buffer Solution has the ability to resist changes in pH upon addition of small amounts of either acid or base Weak acid and its CB (salt of WA) Weak base and its CA (salt of WB) base/ Nucleophile (-) ion or nonmetal (e- rich spp.) Module 1 Soft Large Low High Low Heavy metals: Ag+, Au+, Hg22+/ Hg2+, Cd2+ - (aq) with greater gas moles Temperature + Carbonates/ Bicarbonates + Fat Hard Small High Low High Ions of alkali & alkaline earth metals, H+, NH4, Ti4+, Cr3+ XII. SOLUBILITY PRODUCT CONSTANT (Ksp) Solubility (g/L) Number of grams of solute dissolved in in 1L of saturated solution Molar solubility (mol/L) Number of moles of solute dissolved in 1L of saturated solution Page 6 of 8 RJAV 2022 Predicting formation of precipitate formation (Q ion product constant) computed based on initial concentration: Q < Ksp Q = Ksp Q > Ksp Noyes Whitney equation Dissolution rate is directly proportional to the solute surface area, solute concentration at boundary layer, and diffusion coefficient XIII. ELECTROCHEMISTRY study of the production of electricity from energy released during spontaneous and nonspontaneous chemical reactions 1. Spontaneous Voltaic cells/ galvanic cells REDOX reaction (Anode - Oxidation; Cathode Reduction) Electrons migrate from Anode athode 2. Nonspontaneous Electrolytic cells: Electric current is applied to remove e- and transfer to another cell (Electroplating) XIV. PERIODIC TABLE Antoine Lavoisier first extensive list of elements (~ 33) Metals vs Nonmetals Oxides Good Conductor Malleable Ductile Metallic luster State at RT Johan Wolfgang Dobereiner "Law of Triads" John Newlands "Law of Octaves" Periods Dmitri Mendeleev "Father of Modern Periodic Table" (Lothar Meyer) Atomic Mass/ Weight Henry Moseley "Created Modern Periodic Table" property varies with increasing atomic number Metal Basic Reducing agent Nonmetal Acidic Oxidizing agents Solid (except Hg) x Brittle x X (except I2) Solid, liquid, gas Hg only liquid metal Amphoteric can act as acid or base Malleable ability to be pounced into thin sheets Ductile ability to be drawn into wires A. PERIODIC TABLE Elements: 118 Periods (Horizontal rows): 7 Groups/ Family (Vertical columns): 18 Groups A: Representative elements (s & p block) Groups B: Transition elements (d block) Actinides & Lanthanides: Inner transition elements (f block) Glenn Seaborg Discovered transuranic elements. > Uranium Actinides below lanthanides (exhibit radioactivity; unstable proton-to-neutron ratio) Law of Octaves Every 8th element similar physicochemical property when arranged according to increasing Atomic weight (Ex. H, F, Cl) Octet rule Elements (Atomic nos. 1achieve 8 electrons (stable) Valence e- electron found in outermost shell Group A Valence e- Valence/ charge 1A (Alkali M) 1 +1 2A (Alkaline Earth M) 2 +2 3A (Boron G.) 4A (Carbon G.) 3 4 +3 (+/- 4) Elements (together with other valences, if any) H, Li, Na, K, Rb, Cs, Fr, NH4 Be, Mg, Ca, Sr, Ba, Ra B, Al, Ga, In, Tl (+2, +4) B. PERIODIC TRENDS Ionization energy energy needed to remove outermost electron in neutral atom Electron affinity energy given off when neutral atom gains extra electron Electronegativity ability of an atom to attract electron pair to itself, forming F: most electronegative (most reactive Oxidizing agent) O2: 2nd most electronegative Note: Decrease Top to Bottom; Increase Left to Right Atomic radius ½ difference between nucleus of 2 Metallic property Note: Increase Top to Bottom; Decrease Atomic radius/ Metallic property Module 1 General Chemistry Left to Right (+3, 5A (Nitrogen G.) 5 -3 6A (Oxygen G./ Chalcogens) 7A (Halogens) 8A/ 0 (Inert/ Noble/ Stable Gases 6 -2 O, S, Se, Te, Po 7 8 -1 0 F, Cl, Br, I, At He, Ne, Ar, Kr, Xe, Rn Group B 1B (Coinage M.) 2B (Volatile M.) 3B (Scandium Subgrp) Valence +1 +2 - 4B (Titanium Subgrp) 5B (Vanadium Subgrp) 6B (Chromium Subgrp) 7B (Manganese Subgrp) 8B (Iron Triad) - New Elements Nihonium Moscovium Tennessine Oganesson Page 7 of 8 - +5) Elements Cu (+2), Ag, Au (+3) Zn, Cd, Hg & Hg2 Sc, Y, Lanthanides (La-Lu), Actinides (Ac-Ir) Ti, Zr, Hf V, Nb, Ta Cr, Mo, W Mn, Tc, Re, Bh 1st Triad: Fe, Co, Ni (+2, +3) 2nd Triad (Light): Rh, Ru, Pd 3rd Triad (Heavy): Os, Ir, Pt 113Nh 115Mc 117Ts 118Og RJAV 2022 XV. RADIOACTIVITY Spontaneous emission of particles/ ionizing radiation by unstable nuclei of heavier elements (p+-to-n0 ratio) (atomic # 92 and above: transuranic elements) 10 Non-SI: Curie (Ci) Discovered: Po & Ra SI: Becquerel (Bq) decay/ sec = 1 decay/ sec R.E.M. (roentgen equivalent in man) Unit of radiation damage Rad/ gray Unit of amount of exposure to radiation Radioactive Emissions Radioisotopes decay RANDOMLY Beta & Gamma can penetrate body tissue Rays/ Decay Alpha Mass Velocity Heaviest (4) Beta Light (1/2000) Gamma No mass & charge 0 Slowest (0.1 speed of light) Fast (0.9 speed of light) Fastest (speed of light) Penetrating power Low Prevented by Paper Medium Al High Pb A. MODES OF DECAY particle from the nucleus. For example, polonium210 4 206 210 Po He + Pb or Po 84 2 82 84 - + 4 206 2 82 decay is the emission of an electron from a nucleus. Iodine131 0 131 131 0 131 I e + Xe or I 53 -1 54 53 -1 54 Gamma in an excited state and then decays to its ground state with the -energy electromagnetic radiation. The presence of a nucleus in an excited state is often indicated by an asterisk (*). Cobaltin many applications including cancer treatment: 60 Co* 27 0 60 0 27 nucleus. Oxygen-15 is an example of a nuclide that undergoes positron emission: 15 0 15 15 4 O e + N or O 8 +1 7 8 +1 15 7 Electron capture occurs when one of the inner electrons in an atom is captured -40 undergoes electron capture: 40 0 40 K+e Xe 19 -1 18 Module 1 General Chemistry Page 8 of 8 RJAV 2022