Question

the modern periodic table is arranged in order of increasing atomic ______. mass number radius charge

Explanation:

In the modern periodic table, elements are arranged based on the fundamental property of atomic number. Atomic number represents the number of protons in an atom's nucleus. This arrangement superseded earlier arrangements (like by atomic mass) as it better explains chemical properties and trends. For example, elements in the same group (vertical column) have similar chemical properties because they have the same number of valence electrons, which is directly related to atomic number.

Answer:

number