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Nuclear Energy Science Tracer Bullet (Library of Congress)
Nuclear Power (Wolfram Alpha)
These are organized by a classification scheme developed exclusively for Cosma. More…
CODATA Internationally recommended values of the Fundamental Physical Constants, Atomic and Nuclear (NIST Reference on Constants, Units and Uncertainty)
Radiation, Radioactivity & Radiobiology (Martindale’s Reference Desk)
atom : the smallest particle of an element that can exist either alone or in combination — Webster
Atom is the smallest constituent unit of ordinary matter that has the properties of a chemical element. Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms. Atoms are extremely small; typical sizes are around 100 picometers (a ten-billionth of a meter, in the short scale).
Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and typically a similar number of neutrons. Protons and neutrons are called nucleons. More than 99.94% of an atom’s mass is in the nucleus. The protons have a positive electric charge, the electrons have a negative electric charge, and the neutrons have no electric charge. If the number of protons and electrons are equal, that atom is electrically neutral. If an atom has more or fewer electrons than protons, then it has an overall negative or positive charge, respectively, and it is called an ion.
The electrons of an atom are attracted to the protons in an atomic nucleus by this electromagnetic force. The protons and neutrons in the nucleus are attracted to each other by a different force, the nuclear force, which is usually stronger than the electromagnetic force repelling the positively charged protons from one another. Under certain circumstances, the repelling electromagnetic force becomes stronger than the nuclear force, and nucleons can be ejected from the nucleus, leaving behind a different element: nuclear decay resulting in nuclear transmutation.
The number of protons in the nucleus defines to what chemical element the atom belongs: for example, all copper atoms contain 29 protons. The number of neutrons defines the isotope of the element. The number of electrons influences the magnetic properties of an atom. Atoms can attach to one or more other atoms by chemical bonds to form chemical compounds such as molecules. The ability of atoms to associate and dissociate is responsible for most of the physical changes observed in nature and is the subject of the discipline of chemistry. — Wikipedia
Atomic Physics is the field of physics that studies atoms as an isolated system of electrons and an atomic nucleus. It is primarily concerned with the arrangement of electrons around the nucleus and the processes by which these arrangements change.
The term atomic physics can be associated with nuclear power and nuclear weapons, due to the synonymous use of atomic and nuclear in standard English. Physicists distinguish between atomic physics — which deals with the atom as a system consisting of a nucleus and electrons — and nuclear physics, which considers atomic nuclei alone. — Wikipedia
Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions. Other forms of nuclear matter are also studied. Nuclear physics should not be confused with atomic physics, which studies the atom as a whole, including its electrons. — Wikipedia
Phys.org - latest science and technology news stories Phys.org internet news portal provides the latest news on science including: Physics, Nanotechnology, Life Sciences, Space Science, Earth Science, Environment, Health and Medicine.
Scientists demonstrate ion implantation...
on June 5, 2020 at 3:01 pm
Silicon is the main material in electronic engineering. All information and computing technologies that play a key role in modern civilization are based on silicon: computers, communications, astronautics, biomedicine, robotics and much more.
Cracking open the proton
on June 5, 2020 at 2:51 pm
Physicists around the world are cracking open the proton, within the nucleus of the atom, to see what's inside.
VENUS construction on track for ORNL's newest...
on June 4, 2020 at 7:40 am
Researchers and engineers at the Spallation Neutron Source (SNS) are making progress on the construction of VENUS, the facility's newest instrument for studying materials in exciting new ways that are currently not possible for open research programs in the United States.
The broken mirror: Can parity violation in...
on June 3, 2020 at 12:11 pm
Scientists have long tried to experimentally demonstrate a certain symmetry property of the weak interaction—parity violation—in molecules. So far, this has not been possible. A new interdisciplinary effort led by a research group at the at the PRISMA+ Cluster of Excellence at Johannes Gutenberg University Mainz (JGU) and the Helmholtz Institute Mainz (HIM) has now shown a realistic path to demonstrating this phenomenon. The approach includes aspects of nuclear, elementary particle, […]
The unusual molecular and isotopic content of...
on June 2, 2020 at 2:16 pm
Observations of planetary nebulae have revealed unusual molecular content and surprising enrichments of rare isotopes, challenging both chemical models as well as our current understanding of stellar nucleosynthesis.