atomic mass, the quantity ofmattercontained in anatomof anelement. The observed atomic mass is slightly less than the sum of the mass of theprotons,neutrons, andelectronsthat make up the atom. The difference, called themass defect, is accounted for during the combination of these particles byco...
Atoms,Isotopes,Amu,Averageatomicmass BriefHistoryoftheAtom Around400B.C.Democritus,aGreekphilosopher,proposedthatmatterwasmadeupofsmallhard,indivisibleparticles,whichhecalledatoms AtomicNumber (copythisslide)Atomsarecomposedofelectrons,protons,andneutrons.Theprotonsandneutronsmakeupthesmall,densenucleus.The...
Define atomic mass. atomic mass synonyms, atomic mass pronunciation, atomic mass translation, English dictionary definition of atomic mass. n. The mass of an atom, usually expressed in atomic mass units. American Heritage® Dictionary of the English La
Mass number, in nuclear physics, the sum of the numbers of protons and neutrons present in the nucleus of an atom. The mass number is commonly cited in distinguishing among the isotopes of an element, all of which have the same atomic number (number of p
Atomic Mass of First 30 Elements - Atomic Mass of Elements is Measured with the Help of its Unit - Atomic Mass Unit. One such Unit is Equal to One-Twelfth of the Mass of a Carbon-12 Atom Which is at Rest. Learn about Atomic Mass of First 30 Elements at B
Atomic structure Grams are not used to measure mass of atoms because atoms are too small –Amu is used instead –Amu = atomic mass unit Amu – 1/12 th the mass of a carbon-12 atom, which contains 6 protons and 6 neutrons Isotopes Isotopes are atoms that have the same number of proton...
The mass of a neutron is 1.008 665 u while that of the hydrogen atom is 1.007 825 u. Since both neutrons and protons have almost unit atomic masses, the atomic mass of a nuclide should be close to the number of nucleons, i.e. the mass number. However, when the table of elements ...
and the atomic mass are either very close or else the same. In introductory chemistry, it's probably fine to consider them to mean the same thing. However, there are two cases in which the sum of the protons and neutrons (atomic mass number) is not quite the same as the atomic mass!
What Is Atomic Mass? Atomic massis the sum of the masses of the protons, neutrons, and electrons in an atom, or the average mass, in a group of atoms. However, electrons have so much less mass than protons and neutrons that they don't factor into the calculation. So, the atomic mass...
Atomic mass (ma) is the mass of an atom. Asingle atomhas a set number of protons and neutrons, so the mass is unequivocal (won't change) and is thesum of the number of protonsand neutrons in the atom. Electrons contribute so little mass that they aren't counted. ...