Question

how are the elements in the mendeleev periodic table arranged?
in order of increasing atomic mass.
according to the elements color, crystal shape, and state of matter.
in order of increasing atomic number.
in order of decreasing atomic number.

Explanation:

The elements in the modern - day periodic table (Mendeleev's was a precursor with some differences but the modern principle is similar) are arranged in order of increasing atomic number. Atomic number is the number of protons in an atom's nucleus and is a fundamental property for element classification.

Answer:

In order of increasing atomic number.