From the following isotope notation, detemine the number of protons, neutrons & electrons

so the correct answer would be the 3rd one.

26 proton, 32 neutrons, 26 electrons.

Explanation:

Protons and electrons are the same, which is also the same as the atomic number. in that case that would be 26.

Therefore, proton=electron =26

for neutron, you just have to subtract the mass number to the electron/proton.

n = m - e

n= 58-26

neutron =32.

Hope that helps.

the answer for sodium is 0.186

the answer for rubidium is 0.251