Question

What was the key characteristic by which Dmitri Mendeleev arranged his periodic table?

Responses

increasing atomic radius size
increasing atomic radius size

increasing atomic number

increasing atomic number

increasing atomic mass

increasing atomic mass

increasing number of isotopes

Answer 1

Increasing atomic mass.

Mendeleev arranged elements in order of increasing atomic (relative) mass and grouped elements with similar chemical properties into columns. (Later the periodic table was refined to use increasing atomic number, after Moseley.)