Atom — The smallest particle of an element that can enter into a chemical reaction. Electrons surround the nucleus of an atom because of the attraction between their negative charge and the positive charge of the nucleus. A stable atom will have as many electrons as it has protons. The number of electrons that orbit an atom determine its chemical properties.
See also neutron. Ionizing radiation — Any radiation capable of displacing electrons from atoms , thereby producing ions. High doses of ionizing radiation may produce severe skin or tissue damage.
See also alpha particle , beta particle , gamma ray , neutron , x-ray. Isotope — A nuclide of an element having the same number of protons but a different number of neutrons. Neutrons are, as the name implies, neutral in their charge.
That is, they have neither a positive nor a negative charge. A neutron has about the same mass as a proton. See also alpha particle , beta particle , gamma ray , nucleon , x-ray.
Nucleus — The central part of an atom that contains protons and neutrons. The nucleus is the heaviest part of the atom.
Even though protons and neutrons are about 2, times heavier than electrons, they are tiny. The number of protons is unique for each chemical element. See also nucleon. Radiation — Energy moving in the form of particles or waves. Familiar radiations are heat, light, radio waves, and microwaves. Ionizing radiation is a very high-energy form of electromagnetic radiation. Radioactive decay — Disintegration of the nucleus of an unstable atom by the release of radiation. Although atoms are the smallest units that can exist under normal conditions, high energy physics can smash atoms into their much smaller component parts.
Today atoms are believed to consist mainly of space, with a dense nucleus at their centre. Each nucleus is made of protons which are positively-charged and neutrons which have no charge.
Electrons, which are negatively-charged circulate, around the nucleus in fixed orbits a bit like planets revolving round the Sun. Because the number of protons in any atom is always equal to the number of electrons, atoms have no charge. For example a hydrogen atom consists of one proton and one electron. For example, 40 K potassium has a half-life of 1. Scientists often use these other radioactive elements to date objects that are older than 50, years the limit of carbon dating.
Through the use of radiometric dating, scientists can study the age of fossils or other remains of extinct organisms. Learning Objectives Discuss the properties of isotopes and their use in radiometric dating.
Key Points Isotopes are atoms of the same element that contain an identical number of protons, but a different number of neutrons. Despite having different numbers of neutrons, isotopes of the same element have very similar physical properties.
Some isotopes are unstable and will undergo radioactive decay to become other elements. The predictable half-life of different decaying isotopes allows scientists to date material based on its isotopic composition, such as with Carbon dating. Key Terms isotope : Any of two or more forms of an element where the atoms have the same number of protons, but a different number of neutrons within their nuclei.
What is an Isotope? Carbon or 12 C contains six protons, six neutrons, and six electrons; therefore, it has a mass number of 12 amu six protons and six neutrons. Carbon or 14 C contains six protons, eight neutrons, and six electrons; its atomic mass is 14 amu six protons and eight neutrons.
Radiocarbon Dating Carbon is normally present in the atmosphere in the form of gaseous compounds like carbon dioxide and methane.
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