Definition of atomic mass in English:

atomic mass


  • The mass of an atom of a chemical element expressed in atomic mass units. It is approximately equivalent to the number of protons and neutrons in the atom (the mass number) or to the average number allowing for the relative abundances of different isotopes.

    ‘The atomic mass of an isotope is the total number of protons and neutrons in its nucleus: here 20 and 22 respectively.’
    • ‘Isotopes are atoms of the same element that have slightly different atomic masses due to the presence of differing numbers of neutrons in the nucleus.’
    • ‘He postulated that all the atoms of the same element have the same atomic mass, while the atoms of a different element have a different atomic mass.’
    • ‘Isotopes - versions of elements with different atomic masses - can be used to determine the age of substances.’
    • ‘The atomic masses on the periodic table are expressed in amu.’
    • ‘Uranium's atomic number is 92, its atomic mass is 238.0289, and its chemical symbol is U.’
    • ‘Krypton's atomic number is 36, its atomic mass is 83.80, and its chemical symbol is Kr.’
    • ‘Isotope is the term used for an atom of an element that differs in atomic mass from other atoms of the same element.’
    • ‘After the turn of the century, changes in the model of the atom led to an awareness of a relationship between the atomic mass and the number of particles in the nucleus.’
    • ‘Berkelium is a transuranic element, with an atomic number of 97 and an atomic mass of 274.0703.’
    • ‘In such a case, an element's atomic number and atomic mass should be about equal.’
    • ‘If you have looked at a periodic table you may have noticed that the atomic mass of an element is rarely an even number.’
    • ‘That is, deuterium has twice the atomic mass of protium, and tritium has three times the atomic mass of protium.’
    • ‘Deuterium atoms have an atomic mass of 2, which is double that of normal hydrogen.’
    • ‘Density is a function of the atomic mass of the atoms in the crystal structure and the way they are packed together.’
    • ‘This was the start of the systematization of analytical chemistry and the beginning of rationalization of the atomic mass of the elements.’
    • ‘The baryonic number, which is equivalent to the atomic mass number, has to remain constant for a reaction.’
    • ‘Lithium, with an atomic mass of 6.94, is the lightest of all the metals and is therefore an obvious candidate for battery use.’
    • ‘At this time, chemists knew the atomic masses of elements and their chemical properties, and an astonishing phenomenon jumped out at them!’
    • ‘The sum of protons and neutrons constitutes an element's atomic mass.’
    • ‘Elements of high atomic mass are relatively less stable than objects of lower atomic mass, and are more likely to undergo the process of alpha decay.’


atomic mass

/əˌtämik ˈmas/ /əˌtɑmɪk ˈmæs/