If it is assumed that there are only two isotopes then the percent abundance needs to add up to 100%
100-35= 65%
The second isotope will have a 65% abundance.
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The nucleus consists of protons and neutrons. Since neutrons are neutral, they are not taken account of in the net charge. The number of protons = the net charge of the nucleus and that is shown by the atomic number. For example, the atomic number of Oxygen is 8 which means that it has 8 protons; a net charge of +8 only in the nucleus. On a deeper note, a neutral atom has the same amount of protons as electrons, so theoretically, oxygen is supposed to have 8 valence electrons, but sometimes it has a deficiency of 2 electrons (making an oxygen ion), so the net charge would be -2 of the <em>whole</em> atom (since it's supposed to be neutral), but the net charge of the<em> nucleus</em> itself would still be +8.
Answer: C
Explanation: transferring inner electrons to fill the outer electron ‘shell