An element has a mass of 207 and 125 neutrons in its nucleus. How many protons & electrons does it have & where are they located?

The number of protons can be calculated by subtracting 207 with 125

Therefore, proton no. : 207 - 125

                                    = 32

Proton number and electron number is always equivalent, so there are 32 electrons in the electron shells

Protons and neutrons are always located in the nucleus of an atom, and electrons are located in the electron shells which always move rapidly around the atom

The element which is referred is Lead(Pb)

since electrons are negative the answer is neagtaive