Discuss role of Periodic table in predicting ions formed by atoms of metals and non metals?

Question

Discuss role of Periodic table in predicting ions formed by atoms of metals and non metals?

Answer 1

The columns give the number of electrons in the valence shell. In the first 3 rows (periods), <1/2 filled shells lose e's to revert back to a filled shell (these are metals) while >1/2 filled ones gain to complete the shell (these are non-metals). As the nuclear proton content increases, there is more tendency for the element to lose electrons to revert to last complete shell; thus, the diagonal from boron (3rd column) to Bi (5th column) for metals.