How are the elements arranged in the modern periodic table?

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

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 earlier versions of the periodic table were arranged by increasing atomic mass, but this led to inconsistencies in element properties.
3. Recognize that arranging elements by increasing atomic number resolves these inconsistencies because the atomic number uniquely identifies each element and determines its chemical behavior.
4. Note that the periodic table groups elements with similar chemical properties into columns called groups or families, which arise naturally when elements are ordered by atomic number.
5. Conclude that the correct arrangement of elements in the modern periodic table is by increasing atomic number, not by atomic mass, alphabetical order, or number of neutrons.