The Periodic Table: Classifying Elements

The video discusses the challenges faced by scientists in the 1800s due to the lack of a systematic way to classify elements. Dmitry Mendeleev's attempt to organize elements by atomic mass laid the groundwork for the modern periodic table. Henry Mosley's work on atomic numbers further refined this system, leading to the periodic law that defines today's table, where elements' properties are periodic functions of their atomic numbers.

What was the main challenge faced by scientists in the mid-1800s regarding elements?

• Lack of a systematic classification method

• Lack of funding for research

• Insufficient number of elements

• Inability to conduct experiments

Who was the Russian chemist that attempted to organize the elements systematically?

• Albert Einstein

• Dmitry Mendeleev

• Henry Mosley

• Marie Curie

How did Mendeleev initially arrange the elements in his table?

• Alphabetically

• By increasing atomic mass

• By atomic number

• By chemical reactivity

What significant contribution did Henry Mosley make to the periodic table?

• He discovered new elements

• He introduced the concept of isotopes

• He determined the atomic number of elements

• He arranged elements by atomic mass

According to the periodic law, the properties of elements are periodic functions of what?

• Their atomic mass

• Their density

• Their atomic number

• Their electron configuration