Quis critérios foram usadps por dobereiner em sua tentava de organiza os elementos químicos?

Döbereiner grouped the known elements into triads (sets of three) so that

•The atomic mass of the middle element was approximately the average    of the other two

•The chemical properties of the middle element were between those of the other two

•The physical properties of the middle element were between those of the other two

One example of a triad is Li – Na – K.

(a)Atomic mass of Na = 23.0 u

       Average atomic mass of Li and K = (6.9 u + 39.1 u)/2 = 46.0 u/2 = 23.0 u

(b)Li reacts slowly with water. Na reacts rapidly. Potassium reacts violently.

(c)Melting point of Na = 371 °C.

       Average melting point of Li and K = (454 °C + 330 °C)/2 = 784 °C/2

       = 392 °C

the correct answer would be b) volume versus temperature, because they are also directly proportional.