Question

1. the modern periodic table is arranged in order of increasing:

atomic mass
electron affinity
number of neutrons
atomic number
clear all

Explanation:

The modern periodic table is arranged by increasing atomic number (the number of protons in an atom's nucleus). Atomic mass was used in earlier periodic tables but had inconsistencies. Number of neutrons varies (isotopes) and isn't the basis. Electron affinity is a property related to electron gain, not the arrangement basis.

Answer:

The option with "Atomic number" (the first option among the choices, labeled as "Atomic number" in the provided options).