Crossword-Solution: VALENCY 7 letters, 1 clue 🏆 scrabble score: 15

Couper), led to the introduction of the word equivalent into chemical terminology in a new sense, and in particular to an understanding of the affinities or "valency" of different elements, which proved of the most fundamental importance.

And once the nature of any element has been determined as regards its valency, a most important insight into the possible behavior of that element has been secured.

Hence it is that molecules having all the valency of their atoms fully satisfied do not lose their chemical activity--since each atom is momentarily free in the exchange of partners, and may seize upon different atoms from its former partners, if those it prefers are at hand.

While, however, an appreciation of this ceaseless activity of the atom is essential to a proper understanding of its chemical efficiency, yet from another point of view the "saturated" molecule--that is, the molecule whose atoms have their valency all satisfied--may be thought of as a relatively fixed or stable organism.

Even though it may presently be torn down, it is for the time being a completed structure; and a consideration of the valency of its atoms gives the best clew that has hitherto been obtainable as to the character of its architecture.