Number of protons give atomic number, so Atomic number is 9.
Atomic mass =number of protons +number of neutrons=9+10=19
If we add 1 proton, then atomic number is going to be 10, and it would be Neon,
because number protons define atomic number and so type of element.
If we add neutron, atomic number is not going to change, so it still would be Fluorine, but isotope of Fluorine with different atomic mass that would be equal 20.