It is the electrons that determine the chemical behaviour of a particular element. Isotopes of an element share the same number of protons but have different numbers of neutrons. So different isotopes of the same element are identical, chemically speaking.

Atoms of the same element have the same number of protons, but different isotopes have different numbers of neutrons. Different isotopes of the same element have different masses because they have a different number of neutrons.

Isotopes are atoms of the same element that have different numbers of neutrons but the same number of protons and electrons. The difference in the number of neutrons between the various isotopes of an element means that the various isotopes have different masses.

The rest are radioactive isotopes, also known as “rare isotopes.” Rare isotopes each have unique properties: They live for different amounts of time, from a fraction of a second to a few billion years, and they release different types of radiation and different amounts of energy.

Carbon-13 (13C) is a natural, stable isotope of carbon with a nucleus containing six protons and seven neutrons. As one of the environmental isotopes, it makes up about 1.1% of all natural carbon on Earth.

C-13 is used for instance in organic chemistry research, studies into molecular structures, metabolism, food labeling, air pollution and climate change. C-13 is also used in breath tests to determine the presence of the helicobacter pylori bacteria which causes stomach ulcer.

Radioactive dating is a method of dating rocks and minerals using radioactive isotopes. This method is useful for igneous and metamorphic rocks, which cannot be dated by the stratigraphic correlation method used for sedimentary rocks. Over 300 naturally-occurring isotopes are known.

Radiometric dating, also known as radioactive dating, is what we use to determine the age of rocks. To be more specific, it is a method used to date rocks based on the known decay rate of radioactive isotopes that are found within the rocks.

The absolute age of an Earth material is a measure of how old it actually is in years. Imagine it this way: If you have any siblings, using relative age dating would be like saying, ‘I am older than my brother but younger than my sister,’ but using absolute age dating would be like saying, ‘I am 23 years old.

507 million years old

Layering, or bedding, is the most obvious feature of sedimentary rocks. This Law of Superposition is fundamental to the interpretation of Earth history, because at any one location it indicates the relative ages of rock layers and the fossils in them. Layered rocks form when particles settle from water or air.

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