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  • Nuclear Chemistry

    Bravo – 15,000 kilotons

    Nuclear Chemistry

  • Radioactive elements

  • Radioactive elements

    Elements with atomic numbers greater than 83 are radioactive Why? These elements have too many protons & neutrons crammed into their nucleus to be stable. What happens? The elements “decay” by giving off mass & energy

  • Vocabulary Nuclear Reactions – reactions that effect the nucleus of an atom

    Radioactive Decay –unstable nuclei lose mass (protons/neutrons) & energy to become stable

  • 17 8O

  • Natural transmutation - The nucleus of an atom releases a proton and changes into a different atom. Artificial (man-made) transmutation -The nucleus of an atom is hit with particles that have great quantities of energy. The particles either add to the nucleus or break apart it apart. This changes the atom into a different atom.

    Vocabulary

  • Discovery of Radiation Wilhelm Conrad Roentgen

    • discovered X rays https://easyscienceforkids.com/wilhelm-conrad-roentgen-video-for-kids/

    Pierre & Marie Curie • Coined “Radioactive” • Nobel Laureates • Discovered several radioactive elements

    https://www.biography.com/video/marie-curie-mini-biography-35738691933

    https://easyscienceforkids.com/wilhelm-conrad-roentgen-video-for-kids/ https://www.biography.com/video/marie-curie-mini-biography-35738691933

  • Types of Radiation

    Radiation

    Alpha particles

    Beta particles Positron

    Gamma particles

    • When we are looking at any type of radiation or radioactive decay we must remember that matter is conserved!

  • Nuclear Symbols

    Element symbol

    Mass number (p+ + no)

    Atomic number (number of p+)

    U23592

  • Alpha Particle Emission Beta Particle Emission

    Gamma Ray Emission

    Symbol

    or

    or

    Mass

    Heavy

    Light

    No Mass

    How it changes

    the nucleus

    • Decreases the mass

    number by 4 • Decreases the

    atomic number by 2 • Contains 2 protons

    and 2 neutrons

    • Converts a neutron into a proton

    • Send off a fast moving e- (β)

    • Increases atomic number by 1

    -High energy radiation –just energy! (gamma rays) -No change to the nucleus -emitted with alpha & beta radiation

    Penetration

    Low

    Medium

    High

    Protection

    provided by…

    Paper, clothing

    Cardboard, wood

    Lead

    Danger

    Low, slow moving

    Medium, fast

    High

    He42 α42 e01− β01− γ 0 0

  • Types of Radioactive Decay

    alpha production (α, He): helium nucleus

    beta production (β, e):  gamma ray production (γ):

    ThHeU 23490 4 2

    238 92 +→

    234 234 0 90 91 1Th Pa e−→ +

    γ00 234

    90 4 2

    238 92 2++→ ThHeU

  • Alpha Radiation

    Alpha decay is limited to VERY large, nuclei such as those in heavy metals. (α, He): helium nucleus

  • Alpha particles in a reaction • Alpha radiation is emitted from U-238

    23892U →23490Th + 42He Is matter conserved? Yes!

    • Now you try! • Alpha radiation is emitted from Rn-222 22286Rn →

    218 84Po+ 42He

  • Gamma particles in a reaction

    • 23090Th→22688Ra + 42He + γ – When the alpha particle is released a huge

    amount of energy is also released (the gamma particle)!

  • Beta Radiation

    Beta decay converts a neutron into a proton and an e- (β) is released

  • Beta particles in a reaction • C-14 is a beta emitter, show the decay process • 146C →147N + 0-1β What Happened? • np+; so atomic mass is still 14 • a new p+= atomic number of 7 (now N) • A β-particle flies out of the atom 0

    -1 β is the same as 0-1 e

  • Now you try

    40

    19K →

    40 20Ca + 0-1 β

    What Happened? np+; so atomic mass is still 40 a new p+= atomic number of 20 (Ca) A β-particle flies out of the atom 0

    -1 β is the same as 0-1 e

  • Positron Particle

    • Same mass as an electron • Neutrons can be formed by protons that emit

    a positron • They have a negligible mass

    – Consequently they are more penetrating than alpha particles

    • They have a charge of +1

  • Positrons in a reaction

    • Potassium-38 will emit a positron, show the decay. • 3819K → 3818Ar + 0+1β • What Happened? • p+  n; atomic mass is still 38 • p+  n; atomic number decrease by 1; 18 (Ar) • A positron flies out of the nucleus • Now you try • 137N →

    13 6C + 0+1β

  • Stop and practice

    • Packet page 16-17

    Nuclear Chemistry Radioactive elements Radioactive elements Vocabulary Slide Number 5 � Discovery of Radiation Types of Radiation Nuclear Symbols Slide Number 10 Types of Radioactive Decay Alpha Radiation Alpha particles in a reaction Gamma particles in a reaction Beta Radiation Beta particles in a reaction Now you try Positron Particle Positrons in a reaction Stop and practice