Final answer:
A neutral atom of the lead isotope 207Pb has 82 electrons, 82 protons, and 125 neutrons.
Step-by-step explanation:
For the lead isotope 207Pb, a neutral atom would have the same number of protons as electrons, so it would have 82 electrons and 82 protons.
The mass number, A, of an isotope is the sum of its protons and neutrons. Given that mass number A for 207Pb is 207 and the number of protons (atomic number) is 82.
We can find the number of neutrons by subtracting the atomic number from the mass number. Therefore, 207Pb has 207 - 82 = 125 neutrons.