Periodic table
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Corresponding Wikipedia article: Periodic table
The electron shells of a single atom are the concentric spheres of radii, which are approximately multiples. The electrostatic forces lead the electrons to an uniform distribution over the spherical areas, which are proportional to the squares of radii of these spheres. The maximum number of the electron pairs in each shell is defined by a following sequence:
- 12, 22, 32, 42 = 1, 4, 9, 16
All those numbers except 1 are duplicated.
1a | 2a | 3b | 4b | 5b | 6b | 7b | 8b | 1b | 2b | 3a | 4a | 5a | 6a | 7a | 8a | |||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | |
I | H | He | ||||||||||||||||
II | Li | Be | B | C | N | O | F | Ne | ||||||||||
III | Na | Mg | Al | Si | P | S | Cl | Ar | ||||||||||
IV | K | Ca | Sc | Ti | V | Cr | Mn | Fe | Co | Ni | Cu | Zn | Ga | Ge | As | Se | Br | Kr |
V | Rb | Sr | Y | Zr | Nb | Mo | Tc | Ru | Rh | Pd | Ag | Cd | In | Sn | Sb | Te | I | Xe |
VI | Cs | Ba | La-Lu | Hf | Ta | W | Re | Os | Ir | Pt | Au | Hg | Tl | Pb | Bi | Po | At | Ra |
VII | Fr | Ra | Ac-Lr | Ku | Ns |
The electrons uniformly fill the outer shell and shape a tetrahedron inside the elements of 2nd and 3rd periods, i.e. a dense packing. An unfilled atomic shell is deformed due to the electrons lack or the neighboring atoms influence.
Only elements from the groups 4 (14) … 8 (18) possess a sufficient number of electrons. The tetrahedron is a base cell of the solid crystals and of the spatially structured organic molecules. The tetrahedron deformation produces the unbalanced repulsive forces of electrons and the consequent significant increase in the potential (chemical) energy.
Group | Elements | Valence | Electron shell configuration |
---|---|---|---|
1 | Li, Na, K | 1 | |
2 | Be, Mg, Ca | 2 | Two diametrically opposite points |
3 | B, Al | 3 | Triangle |
4 | C, Si | 4 | Tetrahedron |
5 | N, P | 3 | Tetrahedron with the paired electrons at one vertex |
5 | Irregular shape in the acids and the salts | ||
6 | O, S | 2 | Tetrahedron with the paired electrons at two vertices |
4 | Irregular shape in the ozone and the sulfur dioxide | ||
6 | Irregular shape in the sulfuric acid and the sulfur trioxide | ||
7 | F, Cl | 1 | Tetrahedron with the paired electrons at three vertices |
8 | Ne, Ar | 0 | Tetrahedron with the paired electrons at all vertices |
The elements of 4th and the following periods are forming the amorphous materials due to the irregular shapes of their electron shells. For example, the steel contains the carbon for durability. The irregular shapes of their shells just slightly increase the potential energy of the bonds, because the shell areas are large, and so the electron repulsion forces are weak.
The electronegativity of elements is mainly proportional to their group No., and it decreases with increase in their period. The alkali metals electronegativity is minimal, and the first halogens electronegativity is maximal.
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