Revising The Periodic Table: From Mendeleev To Moseley

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 limitations of Mendeleev's periodic table?

• It was too complex to understand.

• It could not accommodate new elements easily.

• It was not accepted by scientists.

• It was based on atomic numbers.

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

• Physical properties

• Atomic number

• Atomic mass

• Chemical properties

What is the atomic number of an element based on?

• Number of electrons

• Number of neutrons

• Number of protons

• Number of atoms

What does the modern periodic law state?

• Properties of elements are periodic functions of atomic masses.

• Elements are arranged in order of decreasing atomic number.

• Properties of elements are periodic functions of atomic numbers.

• Elements are arranged in order of increasing atomic mass.

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

• By arranging elements based on atomic number

• By placing isotopes in separate tables

• By arranging elements based on atomic mass

• By ignoring isotopes altogether

Why can isotopes be placed together in the modern periodic table?

• They have different chemical properties.

• They have the same atomic mass.

• They have different physical properties.

• They have the same atomic number.

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

• It was easier to memorize.

• It was more colorful.

• It allowed for the prediction of undiscovered elements.

• It was based on atomic masses.

How does the modern periodic table help in placing newly discovered elements?

• By using a random assignment

• By arranging them based on atomic numbers

• By placing them at the end of the table

• By using their chemical properties

What problem did the modern periodic table solve regarding the placement of elements?

• It solved the issue of non-increasing atomic masses.

• It solved the issue of element colors.

• It solved the issue of element shapes.

• It solved the issue of element names.

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

• Mendeleev's Table

• Chemical Properties Table

• Modern Periodic Table

• Atomic Mass Table