Question

How can elements properties be predicted

Answer 1

For predicting its chemical reactivity, generally you look at where it lies on the periodic table, which groups it with metals, semimetals, or nonmentals. Metals combine with nonmetals to form ionic compounds; nonmetals also combine with other nonmetals to form covalent compounds; and metals combine with other metals to form metal alloys (semimetals have intermediate properties). The element's location on the periodic table also defines its specific valence electron structure, and since atoms tend to react so that they have a full octet of valence electrons this will predict the specifics of its bonding behavior. For example, a metal that has only two valence electrons (like nickel) will tend to create a (+2) cation. A nonmetal that has four valence electrons (like carbon) will tend to form four (covalent) bonds.