Which of the following is a characteristic of the modern periodic table?

• A. Elements are grouped solely by their atomic mass.
• B. Periods represent groups of elements with similar chemical properties.
• C. All elements are classified as metals.
• D. Elements are arranged in order of increasing atomic number.

Answer: (D)

Verified step by step guidance

1. Understand that the modern periodic table is organized based on the atomic number of elements, which is the number of protons in the nucleus of an atom.
2. Recall that earlier versions of the periodic table, such as Mendeleev's, arranged elements by increasing atomic mass, but this led to inconsistencies in grouping elements with similar properties.
3. Recognize that in the modern periodic table, elements are arranged in rows called periods and columns called groups or families, where elements in the same group have similar chemical properties.
4. Note that periods represent horizontal rows where properties change progressively, not groups of elements with similar properties; groups (vertical columns) share similar chemical behavior.
5. Conclude that the key characteristic of the modern periodic table is the arrangement of elements in order of increasing atomic number, which resolves previous inconsistencies and better reflects periodic trends.