Electrons Electrons are negatively charged subatomic particles, and they cause electricity when they flow, or static electricity when many of them build up in one place, or are taken away. The electrons have negative electrical charge, and their movement between atoms is responsible for electrical current . This is static electricity . The electrical charge of protons and electrons are exactly equal but opposite. Usually there are the same number of protons and electrons in an atom, and their electrical charges cancel each other.
Electrons surround the atom in pathways called orbitals .
The inner orbitals surrounding the atom are spherical but the outer orbitals are much more complicated. A more accurate picture, according to quantum mechanics, is that the electrons exist in probability distributions , according to which they are not definitely in any specific place at any specific time, but have a greater likelihood of being in one place rather than another. This distribution may be visualised as a 'cloud' The electron cloud has a radius 10,000 times greater than the nucleus. Quantum Physics Bohr developed an improved model of the atom to explain the absorption and emission line spectrum that could not be understood by the Rutherford atom model. The Bohr atom is similar to Rutherford atom, except the electrons can only move in fixed or quantized orbits.