# From what radioactive element does fluorine-19 form by positron emission?

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### 1 Answer

A positron is a particle with a mass of zero and a charge of +1. So to solve, you write a balanced equation so that the atomic numbers and total mass are equal on both sides of the equation.

Element X --> F-19 + positron (mass = 0, charge = +1)

F-19 has an atomic number of +9.

Add the +9 to the +1 for the positron means the unknown element has an atomic number of +10 which is Neon.

The isotope of neon would be Ne-19.