Which isotope is commonly used to date decayed organic matter?

Answer 1

A well-known method is C-14 dating. Carbon 14 is a radioactive isotope of carbon that has half-life of 5730 years, meaning that if you start with 1000 g of C-14, after 5730 years you would have 500 g left (the other half has decayed into N-14). C-14 is present in trace amounts in nature and living organisms would therefore maintain a near-constant level of C-14 in their bodies if they consume and interact with their surroundings. Dead organisms, however, can no longer eat and therefore cannot replenish their C-14 levels, and the C-14 levels would begin to fall due to decay. The amount of C-14 in a dead organism can be compared to a reference level to determine how much time has passed since it died by the formula T = -5730*log2(r/R) where T is the time since the organism's death, r is the remaining level of C-14, and R is the reference level of C-14.

Answer 2

All living things contain carbon, which we all accumulate from our food and from the air. That's true for birds, animals, trees, people; if it's alive, it is bringing in carbon from the environment. When we die, or when a tree dies, we stop taking in carbon from the environment.

Carbon is an element which has 6 protons in the nucleus, and some number of neutrons. The most prevalent are 6 or 7 neutrons, making Carbon either a 12 or 13 mass atom.

There are also several radioactive isotopes, the longest-lived version having 8 neutrons. This carbon-14 isotope decays with a half-life of 5,715 years, and turning into nitrogen. When we breathe in, or eat anything, we're adding a tiny bit of carbon-14 to our bodies - but when we die, this stops.

We know the ratio of normal carbon to carbon-14 in the environment. So if we carefully measure the amount of carbon-12 to carbon-14 in an ancient body, or an ancient tree, we can calculate at least approximately how long it has been since any new c-14 was added; that is, how long it has been dead.

Answer 3

1. C-14 and C-12

because g is organic, compound

Answer 4

Carbon 14