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# basic As level physics help. Watch

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1. Right, I'm doing a paper and it says give the number of the protons, electrons, neutrons of the isotope

55
Fe
26

Surely this is wrong?

Isn't the 26 (atomic number) meant to be where the 55 is, and the 55 (mass) on the bottom?

Otherwise the proton number would = 55 which is wrong, as on the mark scheme it says 26, the botton number?
2. (Original post by Robthriller)
Right, I'm doing a paper and it says give the number of the protons, electrons, neutrons of the isotope

55
Fe
26

Surely this is wrong?

Isn't the 26 (atomic number) meant to be where the 55 is, and the 55 (mass) on the bottom?

Otherwise the proton number would = 55 which is wrong, as on the mark scheme it says 26, the botton number?
Mass number = 55, Atomic = 26

Protons, 26, Electrons, 26, Neutrons, 29.

Well, it should be the other way around, but I am sure you can deduce that the mass number is 55 and not 26.
3. yeah but that is what totally confused me, has it been printed in error as the way round I said, or have they just tried to throw people off?
4. No that's right. I'm looking at my Periodic Table and it represents it as:

55.8
Fe
26

Which is correct, there's no error. The number of protons is always at the bottom and the number of neutrons & protons (mass number) is at the top.
5. Actually, there is no orientation which is 'correct'. Either is acceptable. You will have to get used to this.
6. so the basic rule is that the higher number is the mass? if I remember that then I will be fine?
7. (Original post by StephenP91)
Mass number = 55, Atomic = 26

Protons, 26, Electrons, 26, Neutrons, 29.

Well, it should be the other way around, but I am sure you can deduce that the mass number is 55 and not 26.
Anymore maths jokes?

-----------------------------------
I'm used to mass at the top, proton at the bottom:
4
He
2
8. (Original post by Melanie-v)
Anymore maths jokes?

-----------------------------------
I'm used to mass at the top, proton at the bottom:
4
He
2

haha I found it funny too
9. (Original post by Annie94)
haha I found it funny too
Maths-nerds together

Clever dogs in your sig, btw,.
10. (Original post by Melanie-v)
Maths-nerds together

Clever dogs in your sig, btw,.
haha

11. (Original post by Robthriller)
so the basic rule is that the higher number is the mass? if I remember that then I will be fine?
well logically the mass number can't be lower than the atomic number if you think about it......

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