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The mass number of an atom is the average of all it's isotopes in ratio to how often an isotope occurs naturally (abundance). An isotope is a variant of an element that has a different number of neutrons, therefore causing the atom to have a different mass. The percent abundance of an isotope is converted to a fraction, and multiplied by the mass of the isotope. Then all the factional masses of different isotopes are added together.
Atomic Mass = (mass isotope 1)x(fractional natural abundance of isotope 1) + (mass isotope 2)x(fractional natural abundance of isotope 2) + (mass isotope 3)x(fractional natural abundance of isotope 3)
For example:
Hydrogen has 3 naturally occurring isotopes:
Protium - Abundance - 99.985% (.99985) Mass - 1.0078
Deuterium - Abundance - .015% (.00015) Mass - 2.014
Tritium - Abundance - 0% (.000) Mass - 3.016
Atomic mass number of Hyrdogen = (.99985)(1.0078) + (.00015)(2.014) + (.000)(3.016) = 1.00795
Go look up the mass number of Hydrogen on the Periodic Table and it says 1.008
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What is the atomic mass of a atom?
The atomic mass of an atom is the total mass of protons, neutrons, and electrons in the atom, measured in atomic mass units (amu). It is approximately equal to the sum of the number of protons and neutrons in the atom's nucleus.
What is atomic mass of an atom equal to?
The atomic mass of an element is equal to the number of protons.
Why atomic mass is different from the mass numbers?
atomic mass is the number of protons in an atom mass number is the number of protons plus neutrons in an atom
Is it true that The atomic mass is equal to the atomic number?
No, the atomic mass is not equal to the atomic number. The atomic number represents the number of protons in an atom's nucleus, while the atomic mass is the sum of protons and neutrons in the nucleus. The atomic mass can differ from the atomic number, especially due to the presence of neutrons.
What is the atomic mass of an atom if its mass is approximately one third that of carbon 12?
The atomic mass number of an atom, if the atom's mass number is approximately equal to 0.33 that of carbon-12, would be 4. If the question is about actual masses rather than mass numbers, the mass of a helium-4 atom is about 4.00260 atomic mass units, while the mass of a carbon-12 atom is, by definition, exactly 12.000..... atomic mass units.
The atomic mass of an atom is equal to the sum of numbers of what?
protons + electrons= atomic mass NUMBER, not the atomic mass.
What is the atomic mass of a atom?
The atomic mass of an atom is the total mass of protons, neutrons, and electrons in the atom, measured in atomic mass units (amu). It is approximately equal to the sum of the number of protons and neutrons in the atom's nucleus.
What is atomic mass of an atom equal to?
The atomic mass of an element is equal to the number of protons.
Is the mass number of an atom equal to the atomic number?
Only if the atom is hydrogen-1! The mass number of the atom is equal to the sum of the numbers of protons, which is the same as the atomic number, plus the number of neutrons. The only non-radioactive atom without neutrons is hydrogen-1.
Why doest the atomic number equal the atomic mass?
atomic mass is contributed mainly by protons and neutrons. it is the mass of an atom. atomic number on the other hand is contributed by protons and is equal to the number of protons in the atom
What are the atomic numbers and atomic mass?
Atomic Number :- atomic number of an element is the number of protons present in the nucleus of the atom. (since atoms are electrically neutral the number of protons in an atom is equal to the number of electrons in an atom) Atomic Mass :- atomic mass of an element is the number which tells us how many times an atom of that element is heavier than an atom of hydrogen (whose atomic weight is taken as unity [1])
What atomic mass is equal to the atom on the periodic table?
number of protons = atomic mass
What do atomic number and atomic mass mean?
The atomic number is equal to either the number of electrons or the protons of a particular atom. The atomic mass in a.m.u. is equal to the sum of protons and neutrons in an atom.
Why atomic mass is different from the mass numbers?
atomic mass is the number of protons in an atom mass number is the number of protons plus neutrons in an atom
Is it true that The atomic mass is equal to the atomic number?
No, the atomic mass is not equal to the atomic number. The atomic number represents the number of protons in an atom's nucleus, while the atomic mass is the sum of protons and neutrons in the nucleus. The atomic mass can differ from the atomic number, especially due to the presence of neutrons.
What best describes the number of neutrons in an atom?
It is equal to the difference between atomic number and Atomic Mass number. A+
What is the atomic mass of an atom if its mass is approximately one third that of carbon 12?
The atomic mass number of an atom, if the atom's mass number is approximately equal to 0.33 that of carbon-12, would be 4. If the question is about actual masses rather than mass numbers, the mass of a helium-4 atom is about 4.00260 atomic mass units, while the mass of a carbon-12 atom is, by definition, exactly 12.000..... atomic mass units.
