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

1 Answer
Sep 2, 2016

Answer:

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.