Which of the following best describes how the modern periodic table is arranged?

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

Answer: (B)

Verified step by step guidance

1. Understand that the modern periodic table is organized based on a fundamental property of elements that defines their identity.
2. Recall that the atomic number represents the number of protons in an atom's nucleus, which uniquely identifies each element.
3. Recognize that arranging elements by increasing atomic number places them in order of increasing proton count, reflecting their chemical properties.
4. Note that earlier versions of the periodic table were arranged by increasing atomic mass, but this caused inconsistencies that were resolved by using atomic number instead.
5. Conclude that the modern periodic table is best described as being arranged by increasing atomic number.