How are elements arranged in the modern periodic table?

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

Answer: (B)

Verified step by step guidance

1. Understand that the modern periodic table is organized based on a fundamental property of elements 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 behaviors into the same groups or columns, creating a periodic pattern.
4. Note that earlier versions of the periodic table were arranged by increasing atomic mass, but this led to inconsistencies that were resolved by using atomic number instead.
5. Conclude that the modern periodic table is arranged by increasing atomic number, not by the number of neutrons, atomic mass, or alphabetical order.