Why are atoms usually portrayed as spheres when most orbitals are not spherically shaped?

It is because the orbitals take up a little portion of the atom. The most dense area of the atom is the nucleus which contains the protons and the neutrons. Although it is very small, the mass is concentrated in this part. So, even if the orbitals are not spherical, it does not matter because the nucleus is spherical.

Because electrons have negligible mass, to account for the mass of the isotope, there must be 16 neutrons, 16 neutrally charged, massive, fundamental particles present in the sulfur nucleus. and thus finally, if we have the 32s2− ion, there are 18 electrons, 16 protons, and 16 neutrons.