Understanding the Evolution of the Periodic Table

The video discusses the evolution of the periodic table from Mendeleev's version to the modern periodic table. It highlights the limitations of Mendeleev's table, such as the difficulty in placing new elements and isotopes. Henry Moseley's discovery that elements should be arranged by atomic number, not atomic mass, led to the modern periodic law. This new approach resolved previous issues, allowing for a more accurate and predictive arrangement of elements, including isotopes and undiscovered elements.

What was one of the main challenges with Mendeleev's periodic table as more elements were discovered?

• The table was based on chemical properties only.

• Elements were not fitting into the table according to atomic numbers.

• The table was too small to accommodate new elements.

• Elements were not fitting into the table according to the periodic law.

What did Henry Moseley propose as the basis for arranging elements in the periodic table?

• Atomic number

• Atomic mass

• Physical properties

• Chemical properties

What is the modern periodic law based on?

• The periodicity of chemical properties

• The periodicity of physical properties

• The periodicity of atomic numbers

• The periodicity of atomic masses

How did the modern periodic table resolve the issue of isotopes?

• By placing isotopes in separate tables

• By arranging elements based on atomic masses

• By ignoring isotopes altogether

• By arranging elements based on atomic numbers

Why was the position of hydrogen a limitation in Mendeleev's table?

• It was placed with metals.

• It had no precise position.

• It was placed with non-metals.

• It was placed at the end of the table.

How does the modern periodic table help in predicting the properties of undiscovered elements?

• By using chemical properties

• By using atomic numbers

• By using physical properties

• By using atomic masses

What was a major advantage of the modern periodic table over Mendeleev's table?

• It was based on chemical properties, making it more detailed.

• It was based on atomic masses, making it more accurate.

• It was based on atomic numbers, allowing for easier placement of new elements.

• It was smaller and more compact.

What issue did the modern periodic table resolve regarding the placement of elements?

• The placement of elements with similar atomic numbers

• The placement of elements with similar chemical properties

• The placement of elements with similar atomic masses

• The placement of elements with similar physical properties

Why was the placement of newly discovered elements confusing in Mendeleev's table?

• Because physical properties were not considered

• Because chemical properties were not considered

• Because atomic numbers were not in a constantly increasing order

• Because atomic masses were not in a constantly increasing order

What is the name of the table based on the modern periodic law?

• Mendeleev's Periodic Table

• The Chemical Properties Table

• The Atomic Mass Table

• The Modern Periodic Table