How are the elements on the modern periodic table arranged?

• A. By alphabetical order of element names
• B. By the number of neutrons in the nucleus
• C. By increasing atomic number
• D. By increasing atomic mass

Answer: (C)

Verified step by step guidance

1. Understand that the modern periodic table is organized based on a fundamental property of atoms called the atomic number, which is the number of protons in the nucleus of an atom.
2. Recall that the atomic number uniquely identifies each element and determines its chemical properties, unlike the number of neutrons or atomic mass which can vary among isotopes.
3. Recognize that arranging elements by increasing atomic number places elements with similar chemical properties into the same groups (columns) due to recurring patterns in electron configurations.
4. Note that earlier versions of the periodic table were arranged by atomic mass, but this caused inconsistencies that were resolved by using atomic number instead.
5. Conclude that the correct arrangement of elements in the modern periodic table is by increasing atomic number, not by alphabetical order, number of neutrons, or atomic mass.