Question

A certain nucleus X has a mass number 15 and atomic number 7. Find the number of neutrons. The nucleus X losses one proton and Express the change and write the symbol of the new nucleus.

Answer 1

Mass number = No. of protons + No. of neutrons

Atomic number = No. of protons

∴ No. of neutrons = Mass number - Atomic number 

= 15 - 7 = 8

Element X can be written as \[\ce{_7^15X}\].

After the loss of 1 proton, the mass number and atomic number will decrease by 1. The change can be written as:

\[\ce{_5^15X -> _6^14Y + _1^1P}\]