Isotopes elements used radioactive dating

Based on our study of meteorites and rocks from the Moon, as well as modeling the formation of planets, it is believed (pretty much well-established) that all of the objects in the Solar System formed very quickly about 4.56 billion years ago.When we age date a planet, we are actually just dating the age of the surface, not the whole planet.These differing atoms are called isotopes and they are represented by the sum of protons and neutrons in the nucleus. Carbon has 6 protons in its nucleus, but the number of neutrons its nucleus can host range from 6 to 8.We thus have three different isotopes of carbon: Carbon-12 with 6 protons and 6 neutrons in the nucleus, Carbon-13 with 6 protons and 7 neutrons in the nucleus, Carbon-14 with 6 protons and 8 neutrons in the nucleus.We can get absolute ages only if we have rocks from that surface.For others, all we are doing is getting a relative age, using things like the formation of craters and other features on a surface.The biggest assumption is that, to first order, the number of asteroids and comets hitting the Earth and the Moon was the same as for Mercury, Venus, and Mars. The bottom line is that the more craters one sees, the older the surface is.

The number of protons usually determines the element the atom belongs to and it is fixed for any particular element.

These are the surfaces that we can get absolute ages for.

For the others, one can only use relative age dating (such as counting craters) in order to estimate the age of the surface and the history of the surface.

When the number of neutrons is not in balance with the protons then the atom of that particular element is said to be unstable.

In nature, all elements have atoms with varying numbers of neutrons in their nucleus.