Which corner of the isotope symbol contains the mass number?

1 Answer
Sep 29, 2016

Answer:

The top left corner, as we read the symbol on the page.

Explanation:

When we write #""^12""_6C#, the bottom left symbol is the atomic number #Z#; the top left smbol is the mass number. Since the elemental symbol, the #C#, automatically specifies the atomic number #Z=6#, it is redundant, and may be discarded to give just #""^12C#. Reading this symbol, this tells us that we deal with a nucleon with 6 neutrons in the nucleus, 6 massive, neutrally charged, nucular particles.

For the #""^13C# and #""^14C# isotopes, how many neutrons in each such atom? And how many electrons? Why?