How do we find the number of neutrons in the 31P isotope?

1 Answer
anor277
Jan 20, 2017

Simply subtract 15 from 31:

31−15=number of neutrons in the phosphorus isotope=16

Explanation:

For the 3115P isotope, Z, the atomic number, the subscript, is superfluous. The element is phosphorus, and Z, the atomic number = 15 BY DEFINITION.

The mass number, the superscript, is the number of massive particles, protons and neutrons, contained in the nucleus of the isotope, and this is given by the superscript. This is something you really should get your head round. Hydrogen has 3 common isotopes, 1H,protium,2H,deuterium, and tritium,3H. Can you tell me the number of neutrons each nucleus contains?

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