please help me?

Question

why the semiconductor as whole is neutral having free elctrons

Answer 1

it has electron "holes". these holes form in less than full valence shells. carbon and germanium have half full p orbitals, so they are semiconductors. a more open shell, like copper is an awesome conductor it has a nearly empty valence shell and can accept electrons more rapidly than can an element such as aluminum, which is nearly full

Answer 2

All the atoms in it must have as many electrons as protons, so the whole semiconductor is electrically neutral - even if the electrons can move.