Lab 4 Radioactive (absolute) dating As it explained earlier. dating o.docx

Lab 4 Radioactive (absolute) dating As it explained earlier.
dating or ondering of rock units deposition or geological
events can be done either by relative dating or by radiometric
or radioactive dating. RADIOMETRIC DATING is the
process by which the absolute ne of a rock or geologic event
is determined. This is done using radioactive ISOTOPES,
which are composed of ATOMS having the SAME NUMBER
OF PROTONS but NOT having the SAME NEUTRON
NUMBER, such as, Uranium (U), Potassium (K), Rubidium
(Rb), and Thorium (Th), which are called PARENT
ISOTOPES, and desay by emitting nuclear particles. In the
decay process they are transformed into new isotopes of
different elements called DAUGHTER PRODUCTS,
Eventually, all radianctive isotopes decay to a stable daughter
isotopes. For example, parent uranium isotopes decay through
a series of steps to isotopes of lead and parent potassium
isotopes decay to calcium and argon. ATOMIC NUMBER: is
the number of protons in the nucleus of an atom written as
the subscript of the atom. If it is changed a new element is
produced ATOMIC MASS NUMBER: is the sum of the
number of protons and neutrons in the nucleus of an atom
written as the superscript of the atom. If it is changed no new
elements are produced but a new isotope of the element is
produced. 238 Atomic mass number 92 -_ Atomic number �
Radioactive decay proceeds in three different ways: 1.
ALPHA DECAY: The nucleus of an atom emits an alpha
particle which is composed of two protons and two neutrons.
This loss changes the atomic mass number and also the

atomic number and a new element is produced, e.g., the
decay of Uranium-238 (U92 ) to Thorium-234 (Th90) in the
Uranium decay series. 2. BETA DECAY (ELECTRON LOSS):
The neutron loses a high energy electron and thus converted
into a proton. This loss changes only the atomic number but
not the atomic mass number, and hence new element is
produced, e.g., Rubidium-87 (Rb37) decay to Strontium-87
(Sr38). 3. ELECTRON CAPTURE: is the opposite of beta
decay as an electron is incorporated by a proton in the
nucleus changing into neutron. This changes the atomic
number only but not the atomic mass number, and hence a
new element is produced e.g., Potassium-40 (K19) to Argon-
40 (Aris).
tha +2 D adioactive decay is expressed in terms of a length of
time called a HALF-LIFE. which is defined as the amount of
time necessary for half of the original parent atoms to decay