The operational difference between a pentavalent and a trivalent atom lies in the number of electrons in their outermost energy level, also known as the valence shell.
A pentavalent atom has five electrons in its valence shell. This means it requires three additional electrons to complete its octet (eight electrons in the valence shell) and achieve a stable configuration. Pentavalent atoms tend to gain three electrons through chemical reactions to fill their valence shell and achieve stability. Once they gain these three electrons, they become negatively charged ions with a charge of -3.
On the other hand, a trivalent atom has three electrons in its valence shell. It needs five additional electrons to complete its octet and attain stability. Trivalent atoms often lose these three valence electrons during chemical reactions, resulting in positively charged ions with a charge of +3.
The operational difference between the two lies in their tendency to either gain or lose electrons to achieve a stable electron configuration. Pentavalent atoms have a higher tendency to gain electrons, while trivalent atoms have a higher tendency to lose electrons. This behavior affects their chemical reactivity and the types of compounds they can form.