How can elements properties be predicted?
Elemental properties are predictable by the element position on the periodic table.
Group and Electron Configuration
The group (column) of the periodic table determines the valence electron count. Each element in the Alkali Metal (Li, Na, K, …) IA (1) column has a valence electron configuration of
Metal and Non-metal
The periodic table is divided into metals on the left and non-metals on the right. A staircase is created through the metalloids (B, Si, Ge, As, Sb, Te) dividing the metals from the non-metals. The further left on the periodic table, the more metallic the nature of the element.
Electronegativity is the tendency of an element to attract electrons.
The further right and up on the periodic table, the higher the elements electronegativity. Fluorine has the highest electronegativity of 4.0 and Francium has the lowest electronegativity of 0.7.
The electronegativity can be used to determine the bonding nature of two elements. The difference (subtraction) between the electronegativity value of two elements can be used in a rough scale to determine bonding, 0 to 0.3 Nonpolar-covalent, 0.3 to 1.7 Polar-covalent and 1.7 to 3.3 Ionic.
There are other trends on the periodic table that would provide indicators of how an element may act including, Ionization Energy, Electron Affinity, Atomic Radii and Ionic Radii.
I hope this was helpful.
Nice clicking on the periodic table here: http://chemistry.about.com/library/blperiodictable.htm