What are known as triads?
What are known as triads?
Johann Wolfgang Dobereiner was a chemist in the early 1800s, when the periodic table wasn't in existence, and some chemists were trying to find a type of organizational system for the known elements. Dobereiner noticed a pattern with certain elements that had similar chemical and physical properties. He called these elements triads and, thus, we have Dobereiner's Law of Triads. If you put these elements in order of their atomic masses, the average of the molar mass of the first and third elements in the triad is the molar mass of the second element. Let's look at an example.
The halogens, chlorine, bromine, and iodine, have atomic masses ≈ 35 g/mole, ≈ 80 g/mole, and ≈ 127 g/mole respectively. These values are rounded to the nearest g/mole. If we take the average of the masses of chlorine and iodine we get:
1/2(35 g/mole + 127 g/mole) = 81 g/mole, which is very close to bromine's atomic mass of 80 g/mole
Johann Wolfgang Dobereiner was a chemist in the early 1800s, when the periodic table wasn't in existence, and some chemists were trying to find a type of organizational system for the known elements. Dobereiner noticed a pattern with certain elements that had similar chemical and physical properties. He called these elements triads and, thus, we have Dobereiner's Law of Triads. If you put these elements in order of their atomic masses, the average of the molar mass of the first and third elements in the triad is the molar mass of the second element. Let's look at an example.
The halogens, chlorine, bromine, and iodine, have atomic masses ≈ 35 g/mole, ≈ 80 g/mole, and ≈ 127 g/mole respectively. These values are rounded to the nearest g/mole. If we take the average of the masses of chlorine and iodine we get:
1/2(35 g/mole + 127 g/mole) = 81 g/mole, which is very close to bromine's atomic mass of 80 g/mole
