Asked on 28th Jan, View More. Referral Program Distribute the referral code to your friends and ask them to register with Tutorix using this referral code. Your subscribed friend will also get 1 month subscription absolutely free. Ask Your Doubts We are really eager to clarify your doubts. Join Now. Company About Us. Our Team. Our Faculty. Cobalt has 1 less proton than Nickel. The extra mass comes from having different isotopes that have more neutrons. Elements on the periodic table are ordered according to the number of protons an atom of the element has in its nucleus.
This is called the atomic number. Cobalt has 27 protons while Nickel has 28 - thus Cobalt is first on the table.
Atomic mass , however, has to do with protons and neutrons. Most elements have several isotopes forms of an atom with different numbers of neutrons. I've read a bit about the shell model.
I understand that 28 is a "magic number" of nucleons, i. In that case, wouldn't it be the most stable for both atoms to mainly be found with 28 neutrons; and so, cobalt and nickel would be the most stable isotopes of each element. Why is that not the case? Am I missing or misunderstanding something? As atomic number increases, there is more repulsion and an increasing advantage of spreading out the protons with neutrons.
Calcium is the last greatest atomic number observationally-stable isotope with an equal or greater number of protons than neutrons. Cobalt and Nickel are both unstable to beta decay, because it is favorable to emit a positron converting a proton into a neutron. The natural abundance of isotopes are not necessarily in proportion to the stability, but instead stellar and cosmic processes. Working with Professor W. Fowler of the California Institute of Technology, he had begun with an analysis of the distribution of isotopes of the common metals, and found that nickel presented an unusual case; in the natural metal on Earth, nickel is some three times more abundant than nickel, which is contrary to what one would expect from considerations of nuclear stability.
He found the solution to this puzzle in the effect of neutrino emission from highly evolved stars, leading to extremely short life times, in the range of 20 minutes to 10 hours, and also in the phenomenon of electron-positron pair production. Nickel could be made in an explosion in a large star which occurred so rapidly that the process of synthesis was cut short. So, while the details of that article may be out of date, the reason cobalt has a higher natural abundance atomic mass than nickel is a combination of nuclear stability and stellar processes.
See On the e-process - Its components and their neutron excesses for further discussion of natural abundance ratios of Co and Ni isotopes.
Sign up to join this community.
0コメント