Question

What element can be represented by 45 `n^o`, 34 `p^+`, 34 `e^.`?

Answer 1

If there are `34` `"protons"`, the element is unquestionably `"selenium"`.

Explanation:

The number of protons, the number of massive, positively charged nuclear particles, is `Z,"the atomic number"`. `Z` unequivocally defines the identity of the element. For `Z=34` we have selenium.

We can be even more specific than this, because the question reported the number of neutrons, the number of neutrally charged, nuclear particles, i.e., the `""^79Se` isotope, where the `79` superscript is the isotopic mass: `"neutrons + protons"`. And thus this isotope possesses `79-34=45" neutrons"`

The problem specified `"34 electrons"`, so we know that this is a neutral element. Why?

I haven't looked this up yet, but I think that this is a fission product, i.e. an unusual selenium isotope.