Answer
A triad is a group of three elements for which the middle element has properties that are the average of the properties of the first and third elements.
Some triads include: (0, S, Se); (Cl, Br, I); and (Li, Na, K).
For Li, Na, K
Li Molecular mass = 6.94
Na Molecular mass = 22.9
K Molecular mass = 39.09
Average mass of Li and K = (6.94 + 39.09)/2
= 23 g/mol
Melting point of HCI = -85°C
Melting point of HBr = -66°C
Melting point of HI = -34°C
Average melting point of HCl and HI = [85 + (34)1/2 = 59.5°C
Work Step by Step
A triad is a group of three elements for which the middle element has properties that are the average of the properties of the first and third elements.
Some triads include: (0, S, Se); (Cl, Br, I); and (Li, Na, K).
For Li, Na, K
Li Molecular mass = 6.94
Na Molecular mass = 22.9
K Molecular mass = 39.09
Average mass of Li and K = (6.94 + 39.09)/2
= 23
Melting point of HCI = -85°C
Melting point of HBr = -66°C
Melting point of HI = -34°C
Average melting point of HCl and HI = [85 + (34)1/2 = 59.5°C
