Hi there!

I was wondering if someone could help me out with this question:

Give the symbol, including mass number and atomic number, for the isotope which has a mass number of 34 and which has 18 neutrons in each nucleus.

I originally thought about finding the atomic number which is 34-18=16. And then thought about Oxygen and O-zone. Can they be distinguished as two different sorts of elements due to them being formed as radicals? Or have I got this question totally wrong? Thanks for your help.


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You've got it totally wrong;

You've got it totally wrong; sorry ;-) The atomic mass of O is 16 because it has 8 protons and 8 neutrons, but the unknown element has an atomic mass of 34, 18 of which are neutrons; you have correctly noted that 16 remain but these 16 nucleons are protons so the atomic number must be 16; the element is S, isotope 34.

As for the second part of your guess, a diatomic molecule of O is normal oxygen(O2); ozone is a triatomic molecule of the same element, O3. In this sense it is fundamentally like other allotropic forms of elements like P, As, or Sn.

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