_____ was responsible for first grouping elements into triads based on similar properties.
A. Döbereiner
B. Moseley
C. Dalton
D. Mendeleev
http://en.wikipedia.org/wiki/D%C3%B6bereiner%27s_triads
The answer is A. Döbereiner.
To arrive at this answer, we can apply a few steps:
1. Start by understanding the given question and the options provided. The question asks who was responsible for the first grouping of elements into triads based on similar properties.
2. Research and knowledge about the history of the periodic table can be helpful. The periodic table was created to organize and classify elements based on their properties.
3. Consider each option and eliminate those who are unlikely to be responsible for the mentioned development.
4. Research further to gather information about each remaining option.
5. Based on the research, identify the person who first grouped elements into triads based on similar properties.
Starting with option C, Dalton, John Dalton was an English chemist and physicist who contributed greatly to the development of the atomic theory. However, Dalton did not group elements into triads as mentioned in the question.
Moving on to option D, Mendeleev, this refers to Dmitri Mendeleev, a Russian chemist who is widely recognized for his work in creating the periodic table. While Mendeleev made significant contributions to the periodic table, he did not specifically group elements into triads, which eliminates this option.
Option B, Moseley, refers to Henry Moseley, an English physicist who made groundbreaking contributions to the understanding of atomic numbers and periodic trends. However, Moseley's work is not relevant to the specific task of grouping elements into triads.
Finally, option A, Döbereiner, refers to Johann Wolfgang Döbereiner, a German chemist who was indeed responsible for the first grouping of elements into triads based on similar properties. Döbereiner's triads were based on the concept that elements with similar chemical properties tended to have similar atomic weights.
Therefore, the correct answer is A. Döbereiner.