Dmitri Mendeleev revolutionized chemistry by creating the periodic table, organizing elements by atomic mass and properties. Despite initial challenges, his innovative approach predicted undiscovered elements, proving his method's accuracy and changing the scientific understanding of matter.

Who was the scientist responsible for organizing elements into a natural order, leading to the creation of the periodic table?

• Albert Einstein

• Dmitri Mendeleev

• Isaac Newton

• Marie Curie

What was one of the main challenges scientists faced when trying to categorize elements in the early 19th century?

• Lack of technology

• Varied properties of elements

• Insufficient funding

• Political interference

Which method did some scientists use to group elements before Mendeleev's periodic table?

• By melting point

• By atomic number

• By color

• By reactivity with water

What was Mendeleev's unique approach to organizing the elements?

• Arranging them alphabetically

• Combining properties and atomic weights

• Grouping by color

• Sorting by density

What did Mendeleev predict about the gaps in his periodic table?

• They were errors in calculation

• They represented undiscovered elements

• They were placeholders for isotopes

• They were unnecessary