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Is the atomic weight a whole number?
No, it is not.The atomic mass for an isotope of an element is usually close to a whole number but never exactly so. This is because most elements exist in a number of isotopic forms: they are made up of the same number of protons and electrons but differ in the number of neutrons. So the mass of each isotope of the same element will differ from other isotopes by a whole number of mass units. The atomic mass of the element is the average mass of all its isotopes, weighted together in proportion of the abundance of the elements.The worst offender is dysprosium. The element has 66 proton and electrons 162.5.164-Dy has a mass of 163.929 and accounts for 28.3% of the Dy on earth,162-Dy has a mass of 161.927 and accounts for 25.5% of the Dy on earth,163-Dy has a mass of 162.929 and accounts for 24.9% of the Dy on earth,and there are 4 more isotopes accounting for smaller proportions. When averaged, the atomic mass for Dy is 162.5 - as far from a whole number as you can get!
Explain why the atomic mass of an element is usually not given as a whole number even though each individual atom of the element has a whole number of protons and neutrons.?
There are two reasons. The first is that the masses of protons and neutrons are not 1 unit but slightly greater. The mass of an atom is the mass of a whole number of protons, a whole number of neutrons as well as the same number of electrons as protons. Overall, therefore, the mass should be greater than the number of protons and neutrons (electrons have very little mass). But some of the mass is converted to energy which is used to hold the positively charged nucleus together. As a result the mass of carbon-12 is an exact whole number (12) and that is the only element for which that is true. The second, and possibly more important reason is that most atoms are found in the form of isotopes which have different numbers of neutrons and so different masses. The atomic mass listed for an element is an average of the masses of all these isotopes, weighted together according to their abundance of earth.
What is the most important number in this whole world?
your date of birth...without it you are....nothing (no identity!)
Sara says the number with the most digit is always greatest do you agree Explain?
§ In comparing two whole numbers, the one with the most digits is always the greater number. § In decimals the number with the greatest number of digits is not always the greatest.
Is 40.16 rational?
YES !!!!! Think of all numbers to be rational except, those decimal numbers tha go to infinity AND there is no regular order in the decimal digits. pi = 3.141592.... is the most well known irrational number. However. 123.123123123..... Is rational because the decimal digits are in a regular order.
