Video Transcript
How did Mendeleev order his periodic table? (A) By atomic number, (B) by atomic weight, (C) by color, (D) by date of discovery, or (E) by name.
In 1869, Dmitri Mendeleev published his first periodic table. The elements were organized into rows and columns. The elements increased in atomic weight down a column. And elements that had similar properties were grouped into the same row. Even when Mendeleev revised the table in 1871, the elements were still listed in order of atomic weight, but this time from left to right. Nowadays, the periodic table is ordered by atomic number.
Therefore, the answer to the question “How did Mendeleev order his periodic table?” is (B) by atomic weight.
