Adding or removing protons from the nucleus changes the charge of the nucleus and changes that atom’s atomic number. So, adding or removing protons from the nucleus changes what element that atom is! (Actually, a few neutrons have to be added as well to make the new nucleus stable, but the end result is still helium.)

Changing the number of electrons will change the overall charge on an atom. An atom that loses electrons will become positively charged and an atom with added electrons will become negatively charged. A charged atom is called an ion.

As the number of neutrons in an atom increases or decreases, the isotopes tend to become more and more unstable until they get to the point where they decay faster than neutrons can change. According to the International Atomic Energy Agency, Mercury currently has the most at 45 identified isotopes.

Explanation: It’s very important to keep in mind that the number of protons never changes when dealing with the ion of a chemical element. The only thing that changes is the number of electrons that surround the nucleus of the atom.

Protons and neutrons are tightly bound to the nucleus. The amount of energy required to remove one is far greater than the energy typically found in chemical reactions. Perhaps philosophically, if you change the number of protons of an atom, it no longer retains the identity of that atom.

Erwin Schrodinger’s model of the atom is a more accurate representation of the molecular activity within an atom. Schrodinger’s model is more complex, and was proposed in 1926. His model defeated Bohr’s idea of fixed orbits, thus acknowledging the electrons’ erratic movements.

Because only very few of the alpha particles in his beam were scattered by large angles after striking the gold foil while most passed completely through, Rutherford knew that the gold atom’s mass must be concentrated in a tiny dense nucleus.

The motion of the electrons in the Rutherford model was unstable because, according to classical mechanics and electromagnetic theory, any charged particle moving on a curved path emits electromagnetic radiation; thus, the electrons would lose energy and spiral into the nucleus.

Bohr model was proposed by Niels Bohr in 1915. Quantum model is the modern model of an atom. The key difference between Bohr and quantum model is that Bohr model states that electrons behave as particles whereas quantum model explains that the electron has both particle and wave behavior.

Atomic electron transition is a change of an electron from one energy level to another within an atom or artificial atom. Electron transitions cause the emission or absorption of electromagnetic radiation in the form of quantized units called photons.

If an electron gains energy in an atom then the electron gets excited and forms excited state of an atom. In an atom when electron gains energy the ground state of an atom in which the atom is most stable changes it’s state to exited state in which the atom is less stable than the ground state of atom.