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# Help with this exam question on atomic structure / isotopes

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1. Please can someone tell me how many marks I would get for this question and what I got wrong ?

Thanks
2. (Original post by JackT2000)
Please can someone tell me how many marks I would get for this question and what I got wrong ?

Thanks
I've attached the question here
Attached Images

3. 2 marks first qs
4. 2 marks for 2nd qs
5. 0 marks for 3rd question...it should be 2,8,8,1
6. Mass of electron is nearly 'almost zero' but I think in some GCSE textbooks they do say it is 1/1836 or 1/2000, so it's best to check with the MS what they say.
7. (Original post by sulaimanali)
Mass of electron is nearly 'almost zero' but I think in some GCSE textbooks they do say it is 1/1836 or 1/2000, so it's best to check with the MS what they say.
So what is the mass of the electron? Is it 0?
8. The mass of an electron is around 1/2000th that of a proton, but you can just ignore it because of how small it is. If it asks you for the mass, you can just do protons + neutrons.

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9. You would get 5/6 (possibly 4/6) marks on this practise exam question. Question 4.(a)(iii) would actually be 2.8.8.1 as there are 19 electrons in a potassium atom and you would need to follow the electron shell rules as written below:
- 2 electrons in the first shell.
- 8 electrons in the second shell.
- 8 electrons in the outer shell. (For GCSE).

I am not entirely sure about the last question as it depends on the exam board. Some GCSE books say almost 0 and some say 1. In my exam board, we write it as 0.0005 so you are correct in thinking it is almost 0.
Hope this helps!
Also, what exam board do you follow?
10. (Original post by _bunnieslippers_)
You would get 5/6 (possibly 4/6) marks on this practise exam question. Question 4.(a)(iii) would actually be 2.8.8.1 as there are 19 electrons in a potassium atom and you would need to follow the electron shell rules as written below:
- 2 electrons in the first shell.
- 8 electrons in the second shell.
- 8 electrons in the outer shell. (For GCSE).

I am not entirely sure about the last question as it depends on the exam board. Some GCSE books say almost 0 and some say 1. In my exam board, we write it as 0.0005 so you are correct in thinking it is almost 0.
Hope this helps!
Also, what exam board do you follow?
Thanks my school is on Edexcel for science
11. (Original post by JackT2000)
Thanks my school is on Edexcel for science
So, in this case (due to my handy research skills), you would need to write the relative mass of an electron is 1/1850 for the Edexcel syllabus.

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