Chapter 4 Structure of the Atom

Radiation Radioactivity is the spontaneous emission of particles or energy due to nuclear disintegration. There are three types of natural radiation: Alpha Beta Gamma

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Radiation Alpha Particle (Helium Nucleus) Made of 2 protons & 2 neutrons Positive charge Symbol: α

Radiation Beta Particle Made of high speed electrons emitted from the nucleus of the atom Negative charge Symbol: β

Radiation Gamma rays Made of high energy x-rays No charge Symbol: γ

4.4 Unstable Nuclei and Radioactive Decay The symbol of elements in nuclear reactions is often written as AZX, where A is the mass number, Z is the atomic number, and X is the symbol of the element. For example Uranium- 238 is written as: 23892U

Radioactive molecules decay (decompose) by releasing alpha, beta, and gamma radiation. In alpha decay, 2 protons and 2 neutrons are lost (42He) In beta decay, electrons from the nucleus are lost (0-1e)

During nuclear decay, the number of protons in the atom changes, this is known as transmutation. If the number of protons changes, the identity of the atom also changes.

EX1: Complete the following alpha decay equations: a. 189F  42He + ____ b. 23190Th  42He + ____

EX2: Complete the following beta decay equations: a. 4924Cr  0-1e + ___ b. 2712Mg  0-1e + ___

EX3: Identify the type of nuclear decay: a. 10045Rh  10046Pd + ___ b. 21388Ra  20986Rn + ___

PP1: Complete the following nuclear equations: a. 32He  0-1e + ___ b. 93Li  94Be + ___ c. 21183Bi  42He + ____ d. 19984Po  19582Pb + ___ e. 6130Zn  0-1e + ___ f. 24092U  23690Th + ___ g. 253100Fm  253101Md + ___ h. 8037Rb  42He + ____