physics is not possible due to quantum effects. More than 99.94% of an atom's mass is in the nucleus. Protons have a positive electric charge and neutrons...
125 KB (12,755 words) - 06:17, 26 August 2024
The atomic mass (ma or m) is the mass of an atom. Although the SI unit of mass is the kilogram (symbol: kg), atomic mass is often expressed in the non-SI...
21 KB (2,713 words) - 15:58, 25 August 2024
of the isotopes of the constituent atoms on Earth. The molar mass is appropriate for converting between the mass of a substance and the amount of a substance...
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Rutherford model (redirect from Rutherford atom)
volume in comparison to the rest of the atom and with this central volume containing most of the atom's mass; this region would be known as the atomic...
12 KB (1,558 words) - 00:11, 20 August 2024
Atomic number (redirect from Atom number)
compared to the nucleon mass, the atomic mass of any atom, when expressed in daltons (making a quantity called the "relative isotopic mass"), is within 1% of...
15 KB (1,937 words) - 00:58, 28 August 2024
baryonic mass of the universe. In everyday life on Earth, isolated hydrogen atoms (called "atomic hydrogen") are extremely rare. Instead, a hydrogen atom tends...
39 KB (5,980 words) - 22:40, 27 August 2024
(also known as isotopic) mass of the atom expressed in atomic mass units. Since protons and neutrons are both baryons, the mass number A is identical with...
8 KB (1,101 words) - 02:39, 15 April 2024
Dalton (unit) (redirect from Atomic mass units)
dalton or unified atomic mass unit (symbols: Da or u) is a unit of mass defined as 1/12 of the mass of an unbound neutral atom of carbon-12 in its nuclear...
35 KB (3,683 words) - 21:10, 20 August 2024
used to express mass in units of eV/c2 through mass–energy equivalence the dalton (Da), equal to 1/12 of the mass of a free carbon-12 atom, approximately...
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History of atomic theory (redirect from Atom theory)
scientific theory that matter is composed of particles called atoms. The definition of the word "atom" has changed over the years in response to scientific discoveries...
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Proton (redirect from Proton mass)
charge). Its mass is slightly less than the mass of a neutron and approximately 1836 times the mass of an electron (the proton-to-electron mass ratio). Protons...
68 KB (7,043 words) - 08:17, 22 August 2024
Plum pudding model (redirect from Atom/plum pudding)
The plum pudding model was the first scientific model of the atom with internal structure. It was first proposed by J. J. Thomson in 1904 following his...
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the ratio of the average mass of atoms of a chemical element in a given sample to the atomic mass constant. The atomic mass constant (symbol: mu) is defined...
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Binding energy (redirect from Mass Defect)
nucleus/atom/molecule while retaining their mass, and because of this, it is necessary that they are removed from the system before its mass can decrease...
14 KB (1,342 words) - 19:25, 29 June 2024
Isotope (section Atomic mass of isotopes)
and neutrons) in the nucleus is the atom's mass number, and each isotope of a given element has a different mass number. For example, carbon-12, carbon-13...
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observe individual atoms as they are removed from the sample surface. Through coupling of this magnification method with time of flight mass spectrometry,...
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Bohr model (redirect from Atom/Bohr model)
Bohr model or Rutherford–Bohr model was the first successful model of the atom. Developed from 1911 to 1918 by Niels Bohr and building on Ernest Rutherford's...
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An exotic atom is an otherwise normal atom in which one or more sub-atomic particles have been replaced by other particles of the same charge. For example...
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Mole (unit) (redirect from Gramme-atom)
number of atoms in 12 grams of 12C, which made the mass of a mole of a compound expressed in grams, numerically equal to the average molecular mass or formula...
26 KB (3,298 words) - 15:24, 23 August 2024
Nuclear binding energy (redirect from Mass defect)
is the minimum energy that is required to disassemble the nucleus of an atom into its constituent protons and neutrons, known collectively as nucleons...
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of the accurate masses (including mass defect) of the most abundant naturally occurring stable isotope of each atom in the molecule. For small molecules...
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to the ratio between the mass of desired product to the total mass of reactants, expressed as a percentage. The concept of atom economy (AE) and the idea...
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by which scientists learned that every atom has a nucleus where all of its positive charge and most of its mass is concentrated. They deduced this after...
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Atomic nucleus (redirect from Nucleus of an atom)
surrounding it, bound together by electrostatic force. Almost all of the mass of an atom is located in the nucleus, with a very small contribution from the...
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was so small (less than 0.1%) compared to the known mass of a hydrogen atom. The electron rest mass can be calculated from the Rydberg constant R∞ and...
10 KB (1,498 words) - 17:58, 28 July 2024
Subatomic particle (section Dividing an atom)
In physics, a subatomic particle is a particle smaller than an atom. According to the Standard Model of particle physics, a subatomic particle can be either...
34 KB (3,156 words) - 13:13, 23 July 2024
The Atom (Ray Palmer) is a superhero appearing in American comic books published by DC Comics. The character was created by editor and co-plotter Julius...
66 KB (9,042 words) - 12:25, 3 August 2024
Fast atom bombardment (FAB) is an ionization technique used in mass spectrometry in which a beam of high energy atoms strikes a surface to create ions...
14 KB (1,811 words) - 13:50, 22 June 2024
atomic mass The mass of an atom, typically expressed in daltons and nearly equivalent to the mass number multiplied by one dalton. atomic mass unit See dalton...
171 KB (18,187 words) - 16:16, 23 May 2024