Which achievement is Dmitri Mendeleev best known for in the field of chemistry?

• A. Discovering the electron
• B. Inventing the pH scale
• C. Proposing the law of conservation of mass
• D. Developing the first widely accepted periodic table of elements

Answer: (D)

Verified step by step guidance

1. Understand that Dmitri Mendeleev is a historical figure in chemistry known for organizing chemical elements based on their properties.
2. Recall that the periodic table arranges elements in order of increasing atomic mass (in Mendeleev's time) and groups elements with similar chemical properties together.
3. Recognize that Mendeleev's key achievement was predicting the existence and properties of elements that had not yet been discovered by leaving gaps in his table.
4. Note that other options like discovering the electron, inventing the pH scale, or proposing the law of conservation of mass are attributed to different scientists (J.J. Thomson, Søren Sørensen, and Antoine Lavoisier respectively).
5. Conclude that Mendeleev is best known for developing the first widely accepted periodic table of elements, which laid the foundation for modern chemistry.