Nuclear Chemistry

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Nuclear Chemistry
the study of the structure of atomic nuclei and the changes they undergo
Mass Number
sum of number of neutrons and protons
Atomic Number
above the element on the table -the number of protons in a nucleus
element symbol is the symbol from the periodic table-aka element -A
-isotopes are elements with different number of neutrons but same number of protons
– a changes in isotopes but Z does not
Nuclear Reactions
-occur when nuclei emit particles and/or rays
-atoms often converted into atoms of another element
-may involve, protons, neutron, and electrons
-associated with large energy changes
-reaction rate is not influenced by temp, particle size, concentration, etc.
Alpha Radition
composition- Alpha particles, same as helium nuclei -symbol- Helium nuclei,
-charge- 2+
-mass (amu)- 4
-approximate energy- 5 MeV
-Penetrating power- low (.05 mm body tissue)
-shielding- paper, clothing
Beta Radiation
Beta Radiation:
-composition- beta particles, same as an electron
-symbol e-
-charge- -1
-mass (amu)- 1/1837 (practically 0)
-approximate energy- .05- 1 MeV
-penetrating power- moderate (4 mm body tissue)
-shielding- metal foil
Gamma Radiation
Gamma Radiation:
-composition- high energy electromagnetic radiation
-charge- 0
-mass (amu)- 0
-approximate energy- 1 MeV
-penetrating power- high (penetrates body easily)
-shielding- lead, concrete
Nuclear Stability
Nuclear Stability:
-Isotope is completely stable if the nucleus will not spontaneously decompose
-elements with atomic numbers 1 to 20 are very stable
-1:1 ratio of protons:neutrons

-example: carbon- 12 has 6 protons and 6 neutrons

Types of Nuclear Reactions
-radioactive decay- alpha and eta particles and gamma ray emission

-nuclear disintegration- emission of a proton or neutron

Alpha Decay
alpha decay- emission of an alpha particle denoted by the symbol because an a has 2 protons and 2 neutrons, just like the He nucleus-charge is
-alpha decay causes the mass number to decrease by 4 and the atomic number to decrease by 2
-atomic number determines the element. All nuclear equations are balanced; mass number is balanced
Beta Decay
-beta decay causes no change in mass number and causes the atomic number to increase by 1
-fast moving electron
-mass of 0
-charger is -1
Gamma Decay
-gamma rays- high-energy electromagnetic radiation, denoted by the symbol
– has no mass (0)
-no charge (0)
-causes no change in mass or atomic numbers
-almost always accompany alpha and beta radiation

-there is not effect on mass number or atomic number; usually omitted from nuclear equations

Positron Decay
-emission of a positron is denoted by the symbol
-has insignificant mass (0)
-the charge is 1+
-positron decay causes no change in mass number and causes the atomic number to decrease by 1
Electron Capture
-process in which one of the inner-orbital electrons is captured by the nucleus
-causes no change in mass number
-electron goes on reactant side; left

-causes the atomic number to decrease by 1

Categories: Nuclear Chemistry