Nuclear Chemistry PPT

Nuclear ChemistryPhysical Science 233

VocabularyRadioactivity: Occurs when atoms with unstableisotopes spontaneously emit energy to becomemore stable.Radiation: The energy from radioactivity thatmay take form as a particle (alpha, beta) or aspure energy (gamma).

Remember This?Mass #(p + + n o )Atomic #(p + )13153IAtomicSymbol

Stable vs UnstableStable IsotopeRadioactiveIsotopesMagnesium Iodine Uranium2412127Mg 53 I NoneMg-24 I-1252312125235Mg I U53Mg-23 I-125 U-2352712131238Mg I U53Mg-27 I-131 U-2389292

Types of Radiation• Alpha: A particle that contains 2 protons and 2neutrons.– Because it has 2p + and 2n 0 it has a +2 charge justlike the nucleus of a Helium Atom.– Symbol: α or42 HeAlpha

Types of Radiation• Beta: A particle, a high energy electron with a-1 charge and a negligible mass.– Beta particles are formed when an unstablenucleus transforms a neutron into a proton & ahigh energy e- (β particle).– Symbol: β or 0-1eBeta

Types of Radiation• Positron: A high energy particle similar to anelectron, but with a +1 charge.– Positrons are formed when an unstable nucleustransforms a proton into a neutron & a positron.– Symbol: β + or 0+1ePositron

Types of RadiationGamma Rays: High energy radiation, releasedfrom an unstable nucleus as it rearrangesits particles to give a more stable, lowerenergy nucleus.– Gamma Ray Radiation occurs when a β and a β + collide.The minute masses are completely transformed intoenergy.– Symbol: γ orGamma0γ0

Nuclear Equations• Radioactive decay: The process in which nucleispontaneously break down and emit radiation.

Alpha Decay• Def: An unstable nucleus breaks down to forma new element and an alpha particle.2382344• U → Th + He92902• Uranium → Thorium + Alpha Particle• The sum of the Atomic #’s and mass #’s mustbe the same on both sides of the arrow.

Alpha Decay226884Ra → ____ + He2What isotope belongs in the blank?Answer:226882224Ra → Rn + He862

Beta DecayDef: An unstable nucleus coverts a neutron intoa proton and a β particle.14614C → N + e70-1

Beta DecayFill in the blank. Remember the idea is to keepthe sum of the atomic # and mass # the same.60270Co → + -1 e

Positron Decay• Def: An unstable nucleus converts a protoninto a neutron and a positron.492549Mn → Cr + e240+1

Gamma RadiationDef: An unstable nucleus rearranges and emitsenergy to become more stable.994399Tc → Tc + γ4300Un-StableTechnetiumStableTechnetiumGamma Ray

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