How are the elements ordered on the periodic table?

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

Answer: (A)

Verified step by step guidance

1. Understand that the periodic table is a systematic arrangement of elements based on their properties.
2. Recall that early versions of the periodic table were arranged by increasing atomic mass, but this caused inconsistencies in element placement.
3. Recognize that the modern periodic table is ordered by increasing atomic number, which is the number of protons in an element's nucleus.
4. Know that ordering by atomic number correctly reflects the periodicity of chemical properties and resolves previous inconsistencies.
5. Conclude that the elements are arranged on the periodic table by increasing atomic number, not by atomic mass, alphabetical order, or neutron number.