Nuclear Chemistry

the study of the structure of atomic nuclei and the changes they undergo

sum of number of neutrons and protons

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

-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.

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:
-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:
-composition- high energy electromagnetic radiation
-symbol-
-charge- 0
-mass (amu)- 0
-approximate energy- 1 MeV
-penetrating power- high (penetrates body easily)
-shielding- lead, concrete

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

-radioactive decay- alpha and eta particles and gamma ray emission

-nuclear disintegration- emission of a proton or neutron

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 causes no change in mass number and causes the atomic number to increase by 1
-fast moving electron
-mass of 0
-charger is -1
-electron

-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

-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

-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