92 protons 143 neutrons and and atomic mass of 235 how many electrons does atom have

92.

For all elements, the amount of electrons will always equal the amount of protons. The only time this will change is when it has a charge, for instance, 92 or Uranium, typically has no net charge. If we used the example of Oxygen however, it has a net charge of 2-, meaning that the amount of electrons would increase by 2 to bring Oxygen to stability.

For net charges, the signs mean opposing things: - means gains while + means loses.

Hope this helps!