2 Flashcards
Versions of the same element (same protons) but different atomic weights (different neutrons)
Isotope
Unstable and radioactive isotopes which will decay over time
Parent Element
New element created by the decay of the parent, builds up over time
Daughter Element
The time it takes for half of the parent element to turn into a daughter element
Half-Life
Dating system is useful for very young rocks, fossils, and archeological items. Has 8 neutrons and is unstable, it decays over time
Carbon-14
Has only six neutrons and is stable. The amount will never change
Carbon-12
Dating system useful for very old rock
Uranium-238
Types Of Radioactive Decay
Some unstable isotopes decay by spitting out small particles
Others decay by losing energy and gaining protons
Unstable Parent decays to Daughter in a predictable pattern by ________
halves
What Is A Half-Life?
Closely-packed parent atoms kick of chain reactions
In each unit of time, amount of parents is halved by decay
Dating Example:
Parent isotope absorbed from the air (cosmic rays)
Requires organic matter
Cannot date anything older than 70,000 years
Carbon-14
Dating Example:
Parent isotope common in magma from deep Earth
Good for very old rocks
Cannot date young rocks
Uranium-238
