Atomic structure of Iron

Introduction 
There is a need at all levels of the study of science to present the correct picture of any substance. Here is an attempt to present the correct picture of the Iron atom, which is best described in terms of its orbital structure and orientation.
Occurrence: Iron is one of the more common elements on Earth. It makes up about 5% of the Earth's crust. Most of this iron is found in various Iron oxides, such as the minerals; Hematite, Magnetite, and Taconite. The earth’s core consists largely of a metallic iron-nickel alloy. Although rare, these are the major form of natural metallic iron on the earth's surface.

Atomic structure of Iron

The atomic number of Iron element is 26, which indicates the presence of 26 protons and 26 electrons in its atom.
Naturally occurring Iron consists of four isotopes:
a) 5.845% of radioactive ⁵⁴Fe (half-life: >3.1×10²² years) Number of neutrons, n = 28.
b) 91.754% of stable ⁵⁶Fe, n = 30.
c) 2.119% of stable ⁵⁷Fe, n = 31.
d) 0.282% of stable ⁵⁸Fe, n = 32.
E) ^{6 0}Fe is an extinct radionuclide. n = 34.
Nucleus:
The nucleus of Iron (Fe) atom is made of 26 protons and 30 neutrons (is most abundant).  The total number of electrons in Iron atom is 26, which is equal to that of protons, which maintains the neutrality of the atom.   But, Iron has got two stable oxidation states, +2 and +3.
Electron distribution:
The ground state electronic configuration of Iron atom is given by:
  (1s²)    (2s²2s⁶)    (3s²3p⁶3d⁶)    (4s²)

As it is seen in the electronic configuration, there are four shells available in the Iron atom.
The first energy level - K shell (n=1) - consists of 2 electrons in s-orbital, spherical in shape.
The second energy level - L shell (n=2) - consists of 8 electrons, out of which 2 in s-orbital and 6 in p-orbital (dumb bell in shape).
The third energy level - M shell (n=3) - consists of 14 electrons, out of which 2 in s-orbital and 6 in p-orbital (dumb bell in shape) and 6 in d-orbital (double dumb bell in shape).
The fourth energy level - N shell (n=1) - consists of 2 electrons in s-orbital.
Whenever Iron is oxidized, the electrons are removed from the outermost shell.  An octet electronic configuration is attained when +3 state is reached, which is half filled d-orbital state. So, Fe⁺³ is most stable state of Iron.
 (1s²)    (2s²2s⁶)    (3s²3p⁶3d⁵)    (4s⁰)
Iron is more stable, when it is oxidized.  So, it has a very high tendency to liberate electrons and get converted into Ferric ion, which is reasonable by its atomic structure. This is the reason why Iron gets rust.

Significance of atomic structure

The knowledge of the atomic structure is very useful in describing the chemical as well as physical properties associated with the element. Precisely, it can be said that the secrete of life is hidden in the atomic structure.