1. By calculating the number of valence electron shell, we can gain the geometry array of the electronic pair, and then judge the molecular structures.

2. Metal ion has effects on the surrounding molecules depends on its radius, the charge and the structure of electron shell.

3. According to the periodic table, we selected 16 kinds of metal ions with different ionic charge, radius and electron shell structure in research.

4. Except for the transitional elements, valency electrons are in the outermost electron shell.

5. As many as 2n2 electrons can assigned to an electron shell.