How are the elements on the periodic table primarily organized?

• 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 organized by increasing atomic mass, but this method had inconsistencies.
3. Recognize that the modern periodic table is organized by increasing atomic number, which is the number of protons in an element's nucleus.
4. Know that organizing by atomic number aligns elements with similar chemical properties into columns called groups or families.
5. Conclude that the primary organization principle of the periodic table is by increasing atomic number, not by atomic mass, alphabetical order, or neutron number.