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# specific charge Watch

1. Ok I now that when Cu 63 29 loses 2 electrons that it gains 2 protons, but why is the charge worked out like this 2x1.6x10^19 and not 31x1.6x10^19. Also why is the mass not work out by 65x1.67x10^-21 and why is it 65x1.67x10^-21. Surely when there is 2 more protons the nucleon gets bigger.
2. (Original post by kiwi111)
Ok I now that when Cu 63 29 loses 2 electrons that it gains 2 protons,
You lost me here. How does Cu 29 gain two protons? What process are you describing?
3. (Original post by kiwi111)
Ok I now that when Cu 63 29 loses 2 electrons that it gains 2 protons, but why is the charge worked out like this 2x1.6x10^19 and not 31x1.6x10^19. Also why is the mass not work out by 65x1.67x10^-21 and why is it 65x1.67x10^-21. Surely when there is 2 more protons the nucleon gets bigger.
When an atom loses electrons, it becomes a positive ion. It just means there are more positive charges than negative charges - there is a net charge. It does not mean it gains protons.

When copper-65 loses 2 electrons, it has a net positive charge of +2e which worked out be C. It is usually the net charges that we are concerned in most of the problems not the total charges.
4. (Original post by kiwi111)
Ok I now that when Cu 63 29 loses 2 electrons that it gains 2 protons, but why is the charge worked out like this 2x1.6x10^19 and not 31x1.6x10^19. Also why is the mass not work out by 65x1.67x10^-21 and why is it 65x1.67x10^-21. Surely when there is 2 more protons the nucleon gets bigger.
Hello there,

I struggle to understand what your query is but if I understand you, you are wondering why an atom of Cu-63 has a charge of as opposed to and why its mass is as opposed to .

Firstly, the atom does not gain two protons. This would be the case if this process happened by beta decay, however Cu-63 is a stable atom (https://en.wikipedia.org/wiki/Isotopes_of_copper) and thus does not do this. The atom therefore has basically just lost two electrons, becoming an ion (this may happen during a chemical reaction for example). As electrons are of a negligible mass, the mass of this ion is the mass of the nucleus. The nucleon number has remained unchanged and thus the mass . Before the ionisation, the charge of Cu-63 was . Therefore, the charge on the ion plus the charge of the two missing electrons must be . This implies that the ion charge .

Again, I may not have understood your query so please do not hesitate to ask for further information. I hope that this has been helpful.

Smithenator5000.
5. Yeah im so sorry, in my book I have a question which states : Cu 63 29 loses two electrons. For the ion formed and then it asks for a charge and a specific charge so I got mixed up. Thank you for taking the time to answer my question
6. (Original post by kiwi111)
Yeah im so sorry, in my book I have a question which states : Cu 63 29 loses two electrons. For the ion formed and then it asks for a charge and a specific charge so I got mixed up. Thank you for taking the time to answer my question
I don't know who that was addressed to but you're very welcome.

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Updated: September 18, 2016
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